Explanation -

1/20/25

Along with bees and spiders, snakes have a bad reputation. But contrary to popular belief, these creatures are not normally aggressive. Even rattlesnakes rarely bite unless provoked or threatened. If treated promptly, however, their bites are rarely dangerous.

A. NO CHANGE
B. consequently,
C. moreover,
D. meanwhile,

The first thing to recognize is that the underlined transition is surrounded by commas. This construction indicates that the transition is being used to connect the sentence in which it appears to the previous sentence: in terms of meaning, If treated promptly, transition, their bites are rarely dangerous is the exact equivalent of Transition, if treated promptly, their bites are rarely dangerous. The placement of the transition in the middle of the sentence is purely stylistic.

That said, start by ignoring the transition itself and focus on determining the relationship between the last two sentences. Sentence 1: Snakes rarely bite unless threatened. Sentence 2: Snake bites are rarely dangerous. Those are similar statements, both of which support the idea that snakes’ poor reputation is undeserved. However and meanwhile are used to indicate contrasting ideas, so (A) and (D) can be eliminated. (B) can also be eliminated because therefore is used to indicate a cause-and-effect relationship, and the fact that rattlesnake bites are rarely fatal is not a result of the fact that rattlesnakes rarely bite. Rather, the second statement serves to add additional, related information to the first — a purpose signaled by moreover. That makes (C) correct.

1/19/25

Physicist Michio Kaku, the author of several best-selling books about science, has gained popularity in the mainstream media because of his deep knowledge, and accessible manner of presenting complex scientific subjects.

A. NO CHANGE
B. because of his deep knowledge and accessible manner
C. because of his: deep knowledge and accessible manner
D. because of his deep knowledge and accessible manner,

When two nouns (deep knowlege, accessible manner) are separated by and, no comma should be placed between them. That eliminates (A). (C) is incorrect because a colon must follow a complete, standalone sentence, and clearly Physicist Michio Kaku, the author of several best-selling books about science, has gained popularity in the mainstream media because of his cannot stand on its own as a sentence. (D) is incorrect because when this answer is plugged in, the comma after manner is also placed before the preposition of — and as a rule, no comma should be placed before a preposition. (B) is correct because the underlined portion does not require any punctuation.

1/18/25

The opening of the Empire State Building coincided with the start of the Great Depression. As a result, much of the new skyscrapers’ office space remained empty for months.

A. NO CHANGE
B. skyscraper’s
C. skyscrapers
D. skyscrapers’s

The sentence makes it clear that the underlined noun is referring to the Empire State Building — that’s one skyscraper, singular. (A) can be eliminated because –s + apostrophe is used to make a plural noun possessive, and (C) can be eliminated because an –s without an apostrophe makes a noun plural. (D) can be eliminated because the construction –s + apostrophes + -s is used only to form the possessive of singular nouns that already end in –s (e.g., the dress’s buttons). Skyscrapers’s does not exist. That leaves (B), which correctly forms the singular possessive by adding apostrophe + -s. (Skyscraper’s office space = office space in the skyscraper).

1/17/25

The koala, which is found in coastal areas of the Australian mainland’s eastern and southern regions, can be easily recognized by its stout, tail-less body; large head, and spoon-shaped nose.

A. NO CHANGE
B. stout, tail-less, body, large head, and spoon-shaped nose.
C. stout, tail-less body, large head, and spoon-shaped nose.
D. stout, tail-less body, large head, and, spoon-shaped nose.

When it comes to separating items in a list, commas are almost always the correct option on the SAT and ACT. Nevertheless, either commas or semicolons are grammatically acceptable (semicolons are typically used for clarity when items are long). The only rule is that all the items must be separated by the same type of punctuation — commas and semicolons cannot be mixed and matched. In this case, (A) contains a mix of commas and semicolons, and so it can be eliminated. (D) is incorrect because no comma should be placed after and; a comma can only be placed before this word. Be careful with (B): this answer uses commas to separate all of the items, but it also adds an extra, incorrect comma between the adjective tail-less and the noun body — and as a rule, no comma should ever be placed between an adjective and the noun it modifies. Note that this answer is tricky because the first item consists of two adjectives (stout and tail-less) modifying a noun, whereas the other items consist of one adjective (large, spoon-shaped). As a result, it’s easy to lose track of all the commas. (C) is correct because it places a comma alone between each item in the list and does not place a comma between any adjective and noun.

1/16/25

In ancient Mesopotamia, myths were recorded on clay tablets that writers ascribed with cuneiform derived from Sumerian pictographs. The decision to use clay for a writing surface was ingenious: other writing surfaces people have used in the past deteriorate easily, but not clay, which has proven to be the most durable writing surface ever used.

A. NO CHANGE
B. inscribed
C. subscribed
D. prescribed

Consider the context of the underlined word: the sentence is talking about ancient writing, specifically about recording myths on clay tablets. Logically, the word in question must mean something like “engraved” or “marked.” The only word to fit that definition is inscribed, making (B) the answer. Ascribed means “attributed,” subscribed means “signed up,” and prescribed means “authorized a course of action or treatment.”

1/15/25

Not only have amateur astronomers contributed to many important discoveries, but astronomy also remains one of the few sciences in which non-professionals can still play an active role for.

A. NO CHANGE
B. in which non-professionals can still play an active role.
C. where non-professionals can still play an active role.
D. that non-professionals can still play an active role.

The phrase play an active role is followed by the preposition in, so that preposition — and that preposition only — must appear in the sentence. (A) correctly includes in but then adds a second, unnecessary, preposition (for) at the end of the sentence. (C) is incorrect because where is not an acceptable alternative to in which here: it should only be used to refer to places (physical locations), and astronomy is a scientific field rather than a literal place. (D) is incorrect because the preposition in is omitted: in everyday English, it would be acceptable to say ...one of the few sciences that non-professionals can still play an active role in, but the preposition is absolutely required. (B) correctly uses in which to refer a field of study: non-professionals can still play an active role in astronomy = astronomy is a field in which non-scientists can still play an active role.

1/14/25

Since the early twentieth century, the advertising industry has been a major cultural and economic force, involving almost every form of popular media. The most common goal of advertising is to drive consumer behavior toward a commercial offering, however, political advertising, which aims to convince voters to favor a particular candidate, occurs frequently as well.

A. NO CHANGE
B. offering, however
C. offering however,
D. offering; however,

This question plays on the fact that however has two different grammatical uses that are punctuated two different ways. It can be used non-essentially, in which case it is surrounded by commas, or it can be used to begin a clause, in which case it is placed after a semicolon or period. Note that there is no “one comma” option, either before or after. (B) and (C) are purely “placeholder” answers that stand no chance of being correct. If you’re not sure how however is being used in this sentence, try treating it like a non-essential word and cross it out: The most common goal of advertising is to drive consumer behavior toward a commercial offering…political advertising, which aims to convince voters to favor a particular candidate, occurs frequently as well. No, that’s clearly a run-on. It makes much more sense if the semicolon is used to establish two separate sentences: The most common goal of advertising is to drive consumer behavior toward a commercial offering; however, political advertising, which aims to convince voters to favor a particular candidate, occurs frequently as well. That makes (D) the answer.

1/13/25

Best known as an artist and photographer, Carrie Mae Weems’s first camera was used for political purposes, taking advantage of her position as a union organizer to document the 1960s labor movement.

A. NO CHANGE
B. Best known as an artist and photographer, Carrie Mae Weems used her first camera for political purposes and
C. Carrie Mae Weems, who was best known as an artist and photographer, used her first camera for political purposes,
D. First used for political purposes, Carrie Mae Weems was best known as an artist and photographer,

Who was best known as an artist and photographer? Carrie Mae Weems, not Carrie Mae Weems’s camera, as (A) states. Because Carrie Mae Weems, the subject, does not immediately follow the description that precedes it, this answer contains a dangling modifier. (D) contains the same error in reverse: the introductory phrase used for political purposes clearly describes Weeems’s camera rather than Weems herself. Be careful with (B): this answer does not contain any dangling modification, but when it is plugged in, it creates a different problem: in order for the sentence to be grammatically acceptable, and must be followed by a conjugated verb (Carrie Mae Weems used her first camera for political purposes and took advantage of her position) rather than an -ING word, as is the case here. Although it has a slightly more complex structure than the other answers, (C) is correct. You can test out this answer by removing the non-essential clause to simplify it: Carrie Mae Weems…used her first camera for political purposes, taking advantage of her position as a union organizer to document the 1960s labor movement. Because the sentence makes sense without the clause, it is acceptable. In addition, the -ING word (participle) taking is correctly used to join the underlined portion of the sentence to the last, non-underlined phrase.

1/12/25

When Frank Gehry and his wife bought an existing home in 1977 in Santa Monica, California, the neighbors did not have the slightest idea that the corner residence would soon become an architectural landmark. Gehry, however, wanted to transform the house. His solution was daring for the 1970s: he cut walls, dropped ceilings, and wove the remains with a new architectural framework. From the moment the house was built, Gehry’s neighbors were furious, and controversy ensued.

The writer is considering adding the following phrase to the end of the underlined sentence (placing a period after mesh).

made of industrial shell plywood, glass wire, galvanized metal and metal mesh.

Should the writer make this addition there?

A. Yes, because it provides specific details that help the reader picture the house.
B. Yes, because it explains why Gehry chose such unconventional materials for the renovation.
C. No, because it fails to describe the house’s appearance before Gehry transformed it.
D. No, because it blurs the paragraph’s focus on the reaction of Gehry’s neighbors to the house.

Start by focusing on the information the phrase provides: it’s a list of the unconventional materials Gehry used to create his new architectural framework. In other words, it adds specific and relevant detail, which is almost always a sign that a statement should be added. And indeed, neither of the “No” options fits: the underlined sentence focuses on the house’s new appearance, so its old appearance isn’t relevant in this particular spot. That eliminates (C). (D) can be eliminated because the fact that Gehry’s neighbors were angry is just dropped in at the end of the paragraph — it’s not the main focus. (B) is incorrect as well: the phrase to be added only indicates the materials that Gehry used to renovate the house – it says nothing about why he chose them. (A) is correct because the list of materials provides readers with a more specific sense of the house’s unusual appearance and thus helps them to picture it.

1/11/25

Although it was not the first satellite to be launched, Vanguard 1 was still a remarkable achievement. In addition to demonstrating the technology of a new launcher system, the ground station network, and solar cells, the satellite showed how our planet bulges out around the equator. Equipped with an instrument to measure atmospheric density, it provided the first-ever measurements of the Earth’s tenuous outer atmosphere and an estimate of the number of micrometeorites surrounding the planet – all vital information for future spacecraft.

Based on information in the passage, Vanguard 1 was a “remarkable achievement” because it

A. demonstrated the tenuousness of the Earth’s atmosphere.
B. revealed a lack of uniformity in the earth’s shape.
C. provided an estimate of the number of micrometeorites in space.
D. measured the power generated by solar cells on Earth.

Be very careful with (A): the passage only states that Vanguard I provided the first-ever measurements of the Earth’s tenuous (fragile) outer atmosphere — the achievement was that it measured the atmosphere, not that it demonstrated that the atmosphere was tenuous. (Even if you do not know the definition of tenuous, you can avoid this trap.) (C) is far, far too broad: the passage does state that Vanguard 1 provided…an estimate of the number of micrometeorites, but only those surrounding Earth (the planet), not those in space as a whole. (D) does not fit either because the passage only mentions that Vanguard 1 demonstrated…the technology of solar cells — it says nothing about measuring the power of the energy generated by those cells. (B) is correct because it is directly supported by the statement that the satellite showed how our planet bulges out around the equator. Something that is uniform is consistent or the same, and by definition, a planet that “bulges out” lacks a uniform shape.

1/10/25

Scientists have known for many years that caffeine stimulates the release of the neurotransmitter dopamine, which produces the euphoria and pleasant feelings that people often associate to their first cup of coffee in the morning.

A. NO CHANGE
B. with
C. on
D. DELETE the underlined word.

The correct idiom is associate with; any preposition other than with is incorrect, and removing the preposition entirely creates an ungrammatical construction. That makes (B) correct.

1/9/25

The nine-banded armadillo has two methods of walking through water for short distances, it can walk underwater holding its breath for as long as six minutes, and for long distances, it can increase its buoyancy by swallowing air to inflate its stomach.

A. NO CHANGE
B. water, for short distances,
C. water. For short distances,
D. water for short distances

The key to answering this question is to recognize that this “sentence” is actually two sentences. The construction comma + it, which appears at the end of the underlined portion, signals a comma splice — two complete sentences separated by only a comma. As a result, (A) is incorrect. (B) creates a comma splice as well; it merely moves the comma. This answer can also be eliminated based on the “no comma before a preposition (for) rule.” (D) is incorrect because it fails to place any punctuation at all between the two sentences. (C) moves the phrase for short distances from the end of the first sentence to the beginning of the second in order to create a parallel structure in the second sentence (for short distances…for long distances) and correctly uses a period to separate the two sentences.

1/8/25

Problems with food safety can dissuade people from buying and weaken consumer trust in a particular type of food; however, manufacturers and distributors stand to gain from ensuring that the food system is safe.

A. NO CHANGE
B. therefore,
C. nevertheless,
D. moreover,

Don’t get distracted by the transition in the original version — ignore it and focus on the relationship between the statements before and after the transition. The sentence is essentially saying that 1) problems with food safety cause consumers to stop buying a given food; and 2) manufacturers and distributors stand to gain from ensuring that the food system is safe. Logically, the second idea is the result of the first: food-safety problems lead to decreased sales, SO manufacturers and distributors would want to prevent those problems (i.e., ensure food safety). The only transition to indicate a cause-and-effect relationship is therefore, making the answer (B). However and nevertheless are used to signal contrasting ideas, and moreover is used to connect two similar ideas only — there is no cause-and-effect implication.

1/7/25

Swimming with wildlife can be a life-changing experience. Tiny seahorses delight travelers with their strangely curled tails and bright camouflage while dolphins, which mesmerize onlookers with their acrobatic tricks, keen intelligence, and shiny coats.

A. NO CHANGE
B. dolphins they mesmerize onlookers with their acrobatic tricks,
C. dolphins that mesmerize onlookers, with their acrobatic tricks
D. dolphins mesmerize onlookers with their acrobatic tricks,

The commas surrounding which mesmerize onlookers with their acrobatic tricks suggest that this statement is functioning as a non-essential clause, but when it is crossed out, the sentence that remains does not make any sense: while dolphins…keen intelligence, and shiny coats. That eliminates (A). (B) can be crossed out because the construction dolphins they mesmerize is not acceptable in standard English — it is incorrect for a noun to be immediately followed by a pronoun referring to it. (C) also creates an ungrammatical construction: the verb mesmerize “belongs” to the subject that rather than to its intended subject, dolphins. In addition, the placement of a comma before a preposition (with) is wrong, as is the missing comma after tricks (necessary to separate acrobatic tricks from the other items in the list). (D) correctly pairs mesmerize with its subject, dolphins, and places the required comma after tricks, making it the answer.

1//6/25

The current world record for pumpkin growing is held by Beni Meier, a Swiss accountant who grew a pumpkin that weighs in at 2,323.7 pounds – roughly the same as a small car.

A. NO CHANGE
B. pounds. Roughly
C. pounds, this is roughly
D. pounds; roughly

This is the rare sentence in which one dash does not signal the need for a second dash. Rather, the single dash after pounds is acceptable because it is used to create a dramatic pause between the pumpkin’s weight and the fact that it is comparable to a small car. Even if you’re not sure about that usage, (B) and (D) can be eliminated automatically because a period and a semicolon are interchangeable, and no question can have more than one right answer. (Grammatically, these answers are also wrong because a period and a semicolon can only be used to divide two sentences, and roughly the same as a small car is not a sentence.) (C) can be eliminated because it creates a comma splice — two complete sentences separated by only a comma. In addition, it fails to place a noun after this, a construction that virtually always signals an incorrect answer.

1/5/25

For decades, imaginative engineers and policymakers have dreamt of ways to send human beings to Mars. Some proposals were designed only to inspire. Others truly aimed to put boots on the Martian surface. But they all have one thing in common: they’ve never left the drawing board.

As it is used in the passage, “aimed” most nearly means

A. directed
B. struggled
C. propelled
D. attempted

Given the passage’s focus on people’s desire to go to Mars, aimed must mean something like “had the goal of,” or “were intended to.” If it seems like too much of a leap from that definition to “attempted,” the correct answer, you can play process of elimination. Based on the context of the passage, the correct answer must be positive, so (B), “struggled,” can be eliminated. Next, plug in: it does not make any sense to say Others truly directed to put boots on the Martian surface, so (A) can be crossed out as well. “Propelled” means “launched through the air,” and while it might be logical to describe the movement of an actual spaceship that way, it does not make any sense to refer to the goal of a proposal that way. That again leaves (D), which is correct.

1/4/25

Merlin Tuttle, one of the world’s most respected experts on bats and the author of The Secret Lives of Bats: My Adventures with the Most Misunderstood Mammals, aims to demand popular misconceptions about these often-feared denizens of the night. His work focuses on helping people understand that bats are highly beneficial creatures that make safe neighbors for anyone who leaves them alone.

A. NO CHANGE
B. challenge
C. surpass
D. beat

The information provided by the two sentences indicates that Tuttle has a positive view of bats (His work focuses on helping people understand that bats are highly beneficial creatures). Given that context, Tuttle would logically be opposed to the popular misconception of bats as feared creatures. The only option that conveys that meaning in an idiomatically acceptable manner is (B): to “challenge” a misconception is to question or refute it. The other options have literal meanings that are generally related to challenging but are not idiomatically correct.

1/3/25

In the 1950s, television was the hot technology of the day. While just 9 percent of homes in the United States boasted a TV set in 1950, 56 percent had owned one by 1954, and sales continued to boom for the following decade.

A. NO CHANGE
B. have owned
C. owned
D. own

The presence of dates in the past (1950, 1954), as well as the fact that the surrounding verbs are in the past tense (was, boasted, continued), indicate that the underlined verb should be in the past as well. Although the original version uses the past tense, it is the wrong kind of past tense. When a sentence refers to two finished actions in the past, the past perfect (had owned) should only be used to refer to the action that came first. In this case, that tense is incorrectly used to refer to the action that came second: 1954 happened after 1950. (B) is incorrect because the present perfect (have + verb) is used to describe an action that began in the past but is continuing into the present, but the date 1954 clearly indicates that this action ended in the past. Own is in the present, so (D) can be eliminated as well. (C) is correct because owned is in the simple past, which is consistent with the other verbs in the sentence.

1/2/25

Astronomers hunting for planets outside our solar system keep finding them in the most unexpected places. There are boiling-hot Jupiters that hug their stars, rocky worlds like Earth that spin around multiple suns, and even rogue planets that sail unbounded through the galaxy. Now, astronomers using a gravitational magnifying glass have found a Venus-like planet orbiting a “failed star”—a massive but incredibly dim brown dwarf. This rarely-seen pairing offers clues to the way planets and moons form, which may, in turn, help in the quest to find habitable worlds, whether they are Earth-like planets or life-friendly moons.

The passage suggests that the discovery of a Venus-like planet orbiting a “failed star”

A. is a highly infrequent occurrence.
B. definitively accounts for how planets and moons form.
C. could happen again in the near future.
D. might explain why moons can resemble planets.

The phrase this rarely seen pairing refers to the Venus-like planet and the failed star. It indicates that these types of bodies are not normally found next to one another – by definition, then, they would be discovered “infrequently”. That makes the answer (A). (B) is incorrect because it’s too strong; the passage only states that the discovery may offer clues to how planets form. (C) is exactly the opposite of what the passage states: if Venus-like planets and failed stars don’t normally appear next to one another, scientists probably won’t find another example anytime soon. (D) is incorrect because the passage only states that moons can be habitable. It says nothing about moons resembling planets.

1/1/25

Increasingly, we are learning that humans and animals are not the only organisms that use sound to communicate. Plants and forests use them as well. Plants detect vibrations in a frequency-selective manner, using this “hearing” sense to find water by sending out acoustic emissions and to communicate threats.

A. NO CHANGE
B. it
C. some
D. these

What do plants and forests use as well? The answer is in the previous sentence: sound, singular. As a result, a singular pronoun (it) must be used. Them, some, and these are all plural, eliminating (A), (C) and (D). Only (B) correctly provides a singular pronoun.

12/31/24

In 1872, Yellowstone, the world’s first national park was established, the year the Brooklyn Bridge opened and President Ulysses S. Grant completed his first term in the White House.

A. NO CHANGE
B. Yellowstone, the world’s first national park, was established in 1872,
C. The establishment of Yellowstone, the world’s first national park, in 1872,
D. Yellowstone, established in 1872, was the world’s first national park,

The key to answering this question is to look at the words after the underlined portion: the year. To make the sentence most logical, those words should be placed next to the year (1872) cited in the underlined portion. Otherwise, the modifier (the year the Brooklyn Bridge opened and President Ulysses S. Grant completed his first term in the White House) is separated from 1872, the year it describes. Two options place 1872 at the end of the underlined portion: (B) and (C). When (C) is plugged in, however, a fragment is created. That version of the sentence lacks a main verb that corresponds to the subject, establishment: The establishment of Yellowstone, the world’s first national park, in 1872, the year the Brooklyn Bridge opened and President Ulysses S. Grant completed his first term in the White House. (B) is correct because it contains a main verb (was) that corresponds to the subject (Yellowstone).

12/30/24

Total solar eclipses are rare events: although occurring somewhere on Earth every 18 months on average, they are estimated to recur at any given place only once every 360 to 410 years.

A. NO CHANGE
B. although they occur
C. although they occurred
D. they occur

A statement that begins with a conjunction (although) is a clause, and a clause must contain a conjugated verb rather than an -ING word. That eliminates (A). (C) is incorrect because the verb occurred is in the past tense, and the rest of the sentence is in the present tense (are). (D) is incorrect because if although is removed from the sentence, the result is a comma splice — two complete sentences separated by only a comma. That leaves (B), which correctly retains the conjunction although and supplies a conjugated verb in the present tense.

12/29/24

Many fiber optic companies install more cables than they need, resulting in a system of underground bundled fibers that could be employed for purposes such as earthquake sensing. Each of these fiber optic lines contains imperfections, however. When a light is beamed down the individual fiber optic strands, irregularities in the structure bounce back a fraction of the light.

A. NO CHANGE
B. contain
C. have contained
D. containing

Don’t be fooled by the presence of the plural noun lines immediately before the underlined verb. This noun is actually part of the prepositional phrase of these fiber optic lines, which is used to separate the underlined verb from the subject, each. Each is short for each one and so is singular by definition. (A) is the only option to provide a singular verb (contains), so it is correct. (Remember that singular verbs end in -s.) Don’t be distracted by the tense change in (C): in reality, the question is testing subject-verb agreement only, as is almost always the case on both the SAT and ACT. The incorrect plural verb have is the only thing that counts.

12/28/24

Medical researchers use laboratory-grown human cells to learn the intricacies of how cells work and test theories about the causes and treatment of diseases. The cell lines they need are “immortal”—they can grow indefinitely, remain frozen for decades, and divided them into different batches that are shared among scientists.

A. NO CHANGE
B. divided
C. dividing
D. be divided

The key to answering this question is to recognize that the underlined portion is part of the third item in a list. The rule is that all of the items must be parallel — that is, they must be presented in the same format. The first two items both begin with verbs (grow, remain), so the third item must begin with a verb as well. That eliminates (C) because -ING words are not verbs. Both (A) and (B) begin with verbs; however, neither of these answers fit because each item must be able to follow the verb can: they [cell lines] can grow… can remain frozen… can be divided. If divided alone is plugged in after can, the resulting construction is ungrammatical: it is incorrect to say “they can divided (them) into different batches”… Rather, it is necessary to say that the cells “can be divided into different batches.” That makes (D) the answer.

12/27/24

The artificial sweetener Sucralose is increasingly being used as what experts call a “tracer”—a substance that can help identify the origins of environmental contamination. This use is important for maintaining water quality, both in surface waters and in drinking water supplies.

Which of the following would be the LEAST acceptable alternative to the underlined portion?

A. a tracer, which is a substance
B. a tracer: a substance
C. a tracer; a substance
D. a tracer, a substance

The easiest way to answer this question is to notice that the dash in the original version serves to separate a sentence (The artificial sweetener Sucralose is increasingly being used as what experts call a “tracer”) and a fragment (a substance that can help identify the origins of environmental contamination). As a result, you can assume that the correct answer — that is, the LEAST acceptable answer — will use punctuation that should NOT be used to separate a sentence from a fragment. The only answer that contains such punctuation is (C): a semicolon should only be used to separate two complete sentences.

12/26/24

The smart city is the city of the future: a technological and data-driven urban system designed for efficient growth. Their intended to leverage technology and data to improve the lives of citizens and become more responsive to their needs.

A. NO CHANGE
B. They’re
C. Its’
D. It’s

Logically, the underlined pronoun must refer to the singular noun the smart city — in fact, there is no plural noun to which it can refer. Their and they’re are forms of the plural pronoun they, so (A) and (B) can be eliminated. (C) can be eliminated as well because its‘ does not exist — this answer is wrong whenever it appears. That leaves (D), which is correct because it’s is short for it is, and it makes sense to say It is intended to leverage technology and data to improve the lives of citizens…

12/25/24

An American street photographer born in New York City, Vivian Maier is considered to be one of the greatest photographers of the twentieth century. Despite her artistic legacy and narrative influence on picturemaking, little was known about her until relatively recently. In 2007, meanwhile, the discovery of 100,000 of Maier’s negatives and slides created a portrait of a woman compelled to photograph life on the street. Maier was often her own subject, capturing herself in mirrors, shop windows, and other reflective surfaces. In some, she discreetly made the pictures, almost as if she was spying on herself; in others, her expressionless face is front and center.

A. NO CHANGE
B. however,
C. therefore,
D. moreover,

Remember that when a transition is used between two commas, as is the case here, it serves to connect the sentence in which it appears to the previous sentence — it does not connect two halves of the same sentence. To answer this question, you must therefore back up and consider the relationship between the previous sentence and the information that follows. The previous sentence states that little was known about Maier until relatively recently, whereas the sentence with the transition explains how information about Maier was revealed. Those are opposing ideas, so a contradictor (however) is required, making (B) the only possible answer.

12/24/24

In a series of experiments at Princeton University and the University of California, Los Angeles, students were randomly assigned either laptops or pen and paper for note-taking at a lecture. Those whom had used laptops demonstrated a substantially weaker understanding of the lecture, as measured by a standardized test, than the group using pen and paper. The researchers hypothesized that because students can type faster than they can write, the lecturer’s words flowed right to the students’ typing fingers without stopping in their brains for substantive processing.

A. NO CHANGE
B. Those who
C. Those which
D. They

The rule for who vs. whom is that who rather than whom should always come before a verb. The word following the underlined portion is had, which is a verb, so who is correct. Which should only be used to refer to things, not people, and plugging in they creates an awkward and imprecise construction: those means “the ones,” and the passage is referring to the specific students who used laptops. (B) is thus correct.

12/23/24

Our diet, antibiotic use, and place of birth influence the composition of bacteria in our stomachs. These factors are all important because even slight imbalances in the makeup of our microbiomes can dramatically affect on our vulnerability to disease.

A. NO CHANGE
B. dramatically effect
C. have a dramatic affect
D. have a dramatic effect

If you’re not sure about the difference between affect and effect, you can think RAVEN: (R)emember (A)ffect is a (V)erb and (E)ffect is a (N)oun. In (A) and (B), dramatically is an adverb, which must modify a verb, so it might seem that affect would be the correct answer. But there’s a twist! Look at the word after the underlined portion: on. The noun effect must always proceed it. You can say either dramatically affect x or have a dramatic effect on x, but you cannot say dramatically affect on x. Because you do not have the option of removing on from the sentence, (D) is the only possible answer.

12/22/24

The question of who built the Sphinx has long vexed Egyptologists and archaeologists, but researchers now agree that it was most likely commissioned by Pharaoh Khafre, who ruled in Egypt during the Old Kingdom. It’s known from hieroglyphic texts that Khafre’s father, Khufu, built the 481-foot-tall Great Pyramid, a quarter of a mile from where the Sphinx would later be built. Following this tough act, Khafre constructed his own pyramid, just ten feet shorter than his father’s.

A. NO CHANGE
B. impressive feat,
C. fascinating adventure,
D. awesome stunt,

This question is primarily testing register — that is, whether language is formal or informal. The passage, like nearly all SAT and ACT passages, is written in a neutral, moderately serious tone: neither too academic and sophisticated nor too casual. The correct answer must maintain that tone. “Tough act” and “awesome stunt” are both far too informal, eliminating (A) and (D). In (C), “fascinating” is consistent enough with the prevailing tone, but the passage is describing an achievement, or “feat” (the construction of the Great Pyramid), not an “adventure.” That eliminates (C) and makes (B) the answer.

12/21/24

Regret may be an unpleasant emotion, but it serves an important purpose: it causes people to correct their future behavior in order to avoid harmful consequences. For instance, drivers are understandably furious when they discover their cars have been towed, but they also become more vigilant about reading parking signs and checking for possible violations. Likewise, setting up automatic payments for recurring bills like rent and insurance allows us to reduce the unpleasantness of those transactions.

Which of the following gives a second example most similar to the example already in the passage?

A. NO CHANGE
B. after people have had a particular experience several times, their interest in it begins to decrease.
C. shoppers who are sorry about buying an item are unlikely to make that type of purchase again.
D. repeatedly failing to have our expectations fulfilled causes deep feelings of disappointment.

Although the question asks about the underlined information in terms of examples, you may find it easier to answer this question by focusing on the first (topic) sentence. By definition, an example must support the point it presents. What point is that? Regret…causes people to correct their future behavior in order to avoid harmful consequences. As a result, the correct answer must present information consistent with the idea of regret preventing a future bad decision. (C) is correct because it describes how shoppers who experience regret (“sorry about buying an item”) are prompted to change their future behavior (“unlikely to make that type of purchase again”). (A) and (B) do not describe scenarios that include regret at all, but be careful with (D): “repeatedly failing to have our expectations fulfilled” is generally consistent with the idea of regret, but this answer does not describe how that emotion could lead to future changes in behavior.

12/20/24

Words have tremendous power over our food choice. Giving dishes descriptive names can increase sales by up to 27% in some cases. This becomes particularly effective if the description attaches some provenance to the ingredients – “Grandma’s home-baked zucchini-nut muffins” sound much more appealing than plain “zucchini muffins”.

Naming the farmer who grew the vegetables or the breed of a pig can help to add authenticity to a product. Consumers take that as a sign of quality, even if it has been made up. Sensory words can also make a dish seem more appealing.

A recent study published by scientists at Stanford University found that vegetables that have been given indulgent sounding descriptions – such as “dynamite chili”, “sweet sizzling green beans”, and “crispy shallots” – on a cafeteria menu were picked 23% more often because it made them sound more exciting and flavorsome.

Based on the statement that “Consumers take that as a sign of quality, even if it has been made up,” it can be reasonably inferred that

A. consumers find authentic products more appealing than commercially manufactured ones.
B. consumers are unreliable judges of a product’s authenticity.
C. a high-quality dish will appeal to consumers regardless of its description.
D. knowing a product’s origins leads consumers to purchase high-quality goods.

Start by determining the general context for the statement cited in the question. The passage is discussing the fact that giving (restaurant) dishes descriptive names causes sales to increase. Next, focus on the paragraph in which the statement appears: Naming the farmer who grew the vegetables or the breed of a pig can help to add authenticity to a product. Consumers take that as a sign of quality, even if it has been made up. Sensory words can also make a dish seem more appealing. Taken together, these sentences essentially indicate that customers are seduced by references to products’ origins (naming the farmer who grew the vegetables or the breed of pig), regardless of whether those origins are real or simply invented as a marketing ploy. The statement that consumers take that (the farmer’s name or the breed of pig) as a sign of quality implies that consumers’ ability to determine the reality behind the marketing is limited. In other words, they are “unreliable judges of a product’s authenticity.” That makes (B) the answer.

(A), (C), and (D) are incorrect because the point of the passage is that consumers cannot actually tell the difference between high- and low- quality items: their purchasing behavior is influenced by product descriptions, not by the reality of the products. All of the incorrect options are based on the faulty assumption that consumers can distinguish between description and reality.

12/19/24

Coffee plants use caffeine to ward off insects that would otherwise feast on their leaves and beans. At high doses, caffeine can be toxic to insects; however, some species possess taste receptors that help them avoid to ingest that substance.

A. NO CHANGE
B. of ingesting
C. by ingesting
D. ingesting

The word avoid should be followed by an -ING word (gerund) alone, making (D) the answer. All of the other options are idiomatically unacceptable in context. Don’t get tricked by (C). Although the construction by + -ING does exist, it is used to indicate how something is done and does not make sense logically or grammatically here: “by ingesting” would indicate that some species ingest caffeine in order to avoid a particular consequence, whereas the point of the sentence is that some species do not ingest caffeine.

12/18/24

Recently, a group of planet hunters met in Laramie, Wyoming, to plot better ways to scout for life beyond Earth. Many of these researchers are starting to argue that the existence of liquid water on a planet’s surface (the standard requirement for habitability), is not the factor that should guide exoplanet exploration. Instead, the scientists say, the field should focus on the chances of detecting alien life, should it exist.

A. NO CHANGE
B. requirement for habitability, is
C. requirement for habitability) is
D. requirement for habitability is

The open-parenthesis after surface indicates that a close-parenthesis is necessary, immediately reducing the options to (A) and (C). (A) is incorrect because as a general rule, either commas or parentheses should be used to set off a non-essential clause — it is incorrect to use both forms of punctuation. (C) is correct because it uses parentheses alone to mark the end of the non-essential clause.

12/17/24

There can be no doubt that aircraft cabins are peculiar places for humans to be. Humidity rates are lower then the average desert, while the air pumped into the cabin is cooled as low as 50°F to whisk away the excess heat generated by all the bodies and electronics onboard.

A. NO CHANGE
B. than the average desert,
C. than that of the average desert,
D. than those in the average desert,

This question tests faulty comparisons in two different ways: first, then vs. than. Than should be used to form comparisons, whereas then means “next,” so (A) can be eliminated. Second, consider the comparison: humidity rates are compared to the average desert. Rates must be compared to rates, so (B) can be eliminated. Both (C) and (D) use a pronoun (that, those) to replace the noun rates. Although you may find it odd, this construction is perfectly acceptable. The real issue is singular vs. plural. Rates is plural, whereas that is singular, so (C) can be eliminated as well. Note that the prepositions of and in are both acceptable here; the answer depends only on that vs. those. Humidity rates (in aircraft cabins) are lower than those in the average desert = Humidity rates (in aircraft cabins) are lower than humidity rates in the average desert.

12/16/24

The practice of tipping has spread all over the world, but as international travelers to different countries quickly learn, the customs surrounding tipping – when to tip, how much, to whom and why – can differ substantially from place to place.

A. NO CHANGE
B. to other countries
C. who are traveling abroad
D. DELETE the underlined portion.

International travelers are, by definition, people who “travel to different/other countries” or “who are traveling abroad,” so it is unnecessary to include the phrases in choices (A) through (C). Instead, the underlined portion should be deleted, making (D) the answer. Remember: when you see a DELETE/OMIT option, check it first.

12/15/24

Unwanted eye contact with strangers makes us squirm, and now researchers have figured out why. According to a Reader’s Digest report, looking into someone elses’ eyes makes us more self-aware — and more self-conscious.

A. NO CHANGE
B. else’s eyes
C. elses eyes
D. elses eye’s

Don’t get too distracted by the various placements of the apostrophe. Instead, simplify the question by considering each word separately. Notice that the word else is part of the phrase someone else. By definition, someone is referring to one person, singular, and so else must be singular. Both (C) and (D) place an -s at the end of else, signaling a plural form, so those answers can be eliminated. If you can recognize that in (A), the construction -s + apostrophe also signals a plural form (plural possessive), you can eliminate that answer as well, leaving (B) as the only option. That answer is correct because apostrophe + -s indicates the singular possessive, and the -s alone at the end of eyes indicates the plural: the eyes of someone else.

12/14/24

Unveiled this year at the London Design Festival, the Hyperloop — also known as the “maglev” — is a train made up of linked pods. Using passive magnetic levitation, it glides above a track inside a tube at more than 500 miles per hour. Magnets cause the pods to levitate, while linear motors propel them forward. Although trains are normally subject to bad weather or to naturally occurring impediments such as trees that have fallen across the tracks, but the maglev travels in a controlled environment, free from climatic influences.

A. NO CHANGE
B. and
C. so
D. DELETE the underlined word

As a rule, two consecutive clauses should not both begin with conjunctions. Because the first clause begins with a conjunction (Although trains are normally subject to bad weather or to naturally occurring impediments such as trees that have fallen across the tracks), the second clause should not also begin with a conjunction (but the maglev travels in a controlled environment, free from climatic influences). (D) eliminates the unnecessary conjunction, so it is the only possible option.

There are two things to note here. First, the presence of different types of transitions is a distraction — you do not actually need to worry about the relationship between the clauses, only about the fact that the underlined transition is unnecessary. Second, in order to notice the error, you must back up to the beginning of the (long) sentence. If you focus only on the underlined portion, you’ll have no way of identifying the problem. Even though only one word is underlined, you must actually take the entire sentence into account.

Shortcut: whenever you see a DELETE/OMIT option, particularly on a transition question, check it first because it will most likely be correct.

12/13/24

Some of the most powerful telescopes in the world are now peering across vast distances of space. They are watching for the faintest dip of light or wobble that could suggest the presence of another world.

What is the best way to join the sentence at the underlined portion?

A. space, watching
B. space, and watching
C. space, they are watching
D. space; watching

(A) correctly uses a comma to separate a sentence (Some of the most powerful telescopes in the world are now peering across vast distances of space) and a fragment (watching for the faintest dip of light or wobble that could suggest the presence of another world).

(B) is incorrect because no comma should be placed before and. Comma + and = period, but two sentences are not created when a period is plugged in: Watching for the faintest dip of light or wobble that could suggest the presence of another world is not a sentence.

(C) contains a comma splice — that is, it incorrectly uses a comma to separate two complete sentences (tip-off: comma + they).

(D) is incorrect because a semicolon should only separate two complete sentences. Again, watching for the faintest dip of light or wobble that could suggest the presence of another world is not a sentence.

12/12/24

Columbus, Ohio won a $40 million grant from the U.S. Department of Transportation’s Smart City Challenge in 2016. By 2017, the city had developed several public-private partnerships that turned the $40 million into $500 million in private funding aimed at supporting a smart city project focused on transportation systems. It is unclear if other cities could pull off such a financial feat. Without government funding and strong partners off the bat, city leaders’ ability to raise sufficient funds for a smart city is an uphill battle that cannot be ignored.

The passage implies that other cities may be unable to replicate Columbus’s success in supporting smart city projects because

A. they have inefficient transportation systems.
B. they lack coordination between public and private entities.
C. their technological infrastructure is outdated.
D. city leaders are hampered by financial regulations.

The word “implies” indicates that this is an inference question, so the answer is not stated literally in the passage. Rather, you must put it together from several different statements.

The second sentence states that Columbus was able to successfully support “smart city” projects as a result of several public-private partnerships (coordination between public and private entities) that turned $40 million into $500 million. The following sentences then indicate that it is unclear if other cities could pull off such a financial feat (that is, raising hundreds of millions of dollars) because the type of public-private coordination (government funding and strong partners off the bat) present in Columbus may not exist elsewhere. The implication is that the lack of public-private partnerships in other cities might prevent the success of “smart city” projects. That makes the answer (B).

If you want to play process of elimination, (A) is incorrect because the passage refers to transportation systems but says nothing about their inefficiency. Although the discussion of “smart city” projects and new transportation infrastructure suggests that cities are in need of updating, (C) is incorrect because the passage never states that problems with the existing technological infrastructure will prevent successful completion of new projects. (D) also takes an idea from the passage and “twists” it: the passage does indicate that financial problems are likely to impede “smart city” projects, but it also makes clear that those problems will stem from a lack of collaboration between key players, not from regulations that “hamper” (prevent) city leaders from raising funds.

12/11/24

Brought back from the brink of extinction, the South American vicuna, a llama-like animal, has attracted the attention of poachers eager to profit from: its prized wool.

A. NO CHANGE
B. eager to profit, from its
C. eager to profit from its
D. eager to profit from, its

As a general rule, no punctuation should be used before or after a preposition (from). That eliminates every answer except (C).

This rule is generally tested with commas, as it is in (B) and (D) (and as it was in yesterday’s question as well — this is an important rule to know!). The colon in (A) offers a slight twist on this theme. If you’re not sure about the colon here, you can check it out by looking at the statement that comes before it. A colon must be preceded by a sentence that makes sense as a complete thought, and Brought back from the brink of extinction, the South American vicuna, a llama-like animal, has attracted the attention of poachers eager to profit from clearly cannot stand on its own as a sentence.

12/10/24

Prey-and-predator arms races are not unusual, in the animal kingdom and neither is deception. Deceptive evolutionary adaptations such as camouflage suggest that illusions are not only “errors of perception” but also provide significant advantages to the creatures that produce them.

A. NO CHANGE
B. unusual in the animal kingdom,
C. unusual, in the animal kingdom,
D. unusual in the animal kingdom

If you know that a comma should not be placed before a preposition (in), you can eliminate both (A) and (C) right away. Now, the key to deciding between (B) and (D) is to focus on the word after the underlined portion. (B) places a comma before and, whereas (D) does not. Comma + and = period, so plug in a period. If two sentences are present, then the comma is necessary.

Sentence 1: Prey-and-predator arms races are not unusual.
Sentence 2: Neither is deception.

Those are two complete sentences, so the comma is required, and the answer is (B).

Note that you could potentially get right the answer by sensing that a comma was necessary before and, but that approach would leave you open to second-guessing yourself. If you stopped and went back and forth between (B) and (D), it would also be far more time-consuming.

12/9/24

A study from the University of Cologne in Germany showed that by cleverly naming dishes with words that mimic the mouth movements associated with eating, restaurants could increase the palatability of the food. Researchers found words that move from the front to the back of the mouth — such as the made-up word “bodok” — were particularly effective. Therefore, the effect seems to work even when people read silently, perhaps because the brain still stimulates the motor movements required to produce speech when reading.

A. NO CHANGE
B. However, the effect seems to work
C. Subsequently, the effect seems to work
D. Indeed, the effect seems to work

This is a transition question, so start by ignoring the underlined transition — if you focus on the version already in the passage, you might be tempted to justify a relationship that doesn’t really exist. Next, consider the relationship between the sentence begun by the transition and the previous sentence.

Sentence 1: names that move from the front to the back of a speaker’s mouth made certain dishes more appealing to restaurant diners.

Sentence 2: People also find those dishes more appealing when they read the names silently.

Those are similar ideas. However indicates a contrast, so (B) can be eliminated right away.

Subsequently means “then” or “next” and is used to indicate that one event happened after the other; however, the passage is not describing a sequence of events — it is merely stating two related facts about the effects of dish names on diners’ perception. (C) can thus be eliminated.

Be careful with therefore: this transition is used to indicate that two statements contain similar ideas, but it should only be used to indicate a cause-and-effect relationship — and that is not the case here. The fact that words that move from the back to the front of the mouth make dishes sound more appealing even when read silently is not a result of the fact that such words have the same effect when read aloud. (A) can thus be eliminated as well.

(D) is correct because indeed serves to emphasize a preceding statement. The first previous sentence states that the back-to-front-of-mouth movement is particularly effective, and the sentence begun by the transition reinforces that statement by indicating that it holds true even when the words are not spoken aloud.

12/8/24

To date, astronomers have catalogued thousands of exoplanets, more than a dozen of them are potentially habitable. The most recent is Ross 128b: an Earth-sized planet orbiting a nearby star, it is probably located at a distance that would allow for liquid water.

A. NO CHANGE
B. exoplanets, more than a dozen of which
C. exoplanets; more than a dozen of which
D. exoplanet, more than a dozen of these

The original version contains a comma splice: two complete sentences separated by a comma. (Note that more than a dozen of them are potentially habitable is a sentence, even though it does not make a lot of sense out of context.) (D) is incorrect because it creates a comma splice as well. In addition, these should be followed by a noun (e.g., these planets) — it should not be left “hanging” on its own. (C) is incorrect because it places a semicolon between a sentence and a fragment: more than a dozen of which are potentially inhabitable cannot stand on its own as a complete sentence. (B) correctly places a comma between a complete sentence and a fragment.

12/7/24

In a study of 39 elite cyclists, Oxford University researcher Kieran Clarke and others found the athletes were able to go 400 meters further in half an hour after drinking a ketone drink than after drinking a carbohydrate- or fat-based energy drink. One reason for the increased performance could be that the ketones prevented their bodies from producing too much lactate, which causes people to feel achy after strenuous exercise. Rats on a ketone diet have also run farther on a treadmill and completed a maze faster than rats on a regular diet.

The passage implies that carbohydrate- and fat-based energy drinks

A. may not inhibit the production of lactate.
B. help athletes work out more strenuously.
C. have no effect on athletic performance.
D. are more effective than ketone-based energy drinks.

The word “implies” in the question indicates that this is an inference question, so the answer is not stated word-for-word in the passage. Rather, you must “put the pieces together” yourself.

The passage focuses on the performance benefits of ketone-based energy drinks vs. the lack of benefits from fat- or carbohydrate-based energy drinks. As a result, the correct answer must be consistent with the idea that fat- and carbohydrate-based energy drinks are less effective than ketone-based drinks (negative idea). Based on that information, (D) can be eliminated, and you can make an educated assumption that (B) is wrong as well.

Be careful with (C): the passage only states that athletes were able to go 400 meters further in half an hour after drinking a ketone drink than after drinking a carbohydrate- or fat-based energy drink. The only implication is that the fat- or carbohydrate-based drinks were less effective than the ketone-based ones. It is still possible that the ketone-based drinks had some effect on the athletes’ performance.

(A) is correct because the passage states that one reason for the increased performance could be that the ketones prevented their bodies from producing too much lactate, which causes people to feel achy after strenuous exercise. If ketone-based drinks may improve performance because they stop people from producing too much lactate, then logically, fat- or carbohydrate-based drinks may not be as effective because they do NOT stop people from producing much lactate. In other words, “they may not inhibit the production of lactate.”

12/6/24

Traditional methods of making pottery are still used by a number of Native American tribes, and wares are produced by them for practical use as well as sale to collectors.

A. NO CHANGE
B. tribes, wares being produced by them
C. tribes that produce wares
D. tribes, they produce wares

Both (A) and (B) are wordy and awkward, and contain passive constructions (wares are/being produced by them rather than the active, they produce wares). In addition, the word being, which appears in (B), almost always signals an incorrect answer.

(D) contains a comma splice — two complete sentences separated by only a comma (tip-off: comma + they).

That leaves (C): the plural verb produce agrees with the plural subject tribes and logically indicates that Native American tribes are the source of the wares.

12/5/24

There are many theories about why flying might leave passengers more vulnerable to crying – sadness at leaving loved ones, excitement about the trip ahead, homesickness. But there is also some evidence that flying itself may also be responsible. An emerging body of research is suggesting that soaring 35,000 ft above the ground inside a sealed metal tube can have strange effects on our minds, affecting our sleep cycles and causing drowsiness.

A. NO CHANGE
B. increasing the pressure in our ears and nose.
C. altering our moods and changing our perception.
D. restricting our movements and causing our muscles to stiffen.

To answer this question, you must identify the statement that follows most logically from the beginning of the sentence. The key phrase is strange effects on our minds, so the correct answer must logically describe the mental effect of flying. Affected sleep cycles, increased pressure in the ears and nose, and restricted movements are all physical rather than mental effects of flying. (A), (B), and (D) can thus be eliminated. That leaves (C): altered moods and perception are consistent with the idea that flying can alter passengers’ mental states.

12/4/24

A major reassessment of dinosaurs that began in the 1960s and finally took hold in the 1980s positioned these creatures not as dull evolutionary failures but as active, warm-blooded, animals.

A. NO CHANGE
B. active warm-blooded, animals.
C. active, warm-blooded animals.
D. actively warm-blooded animals.

A comma should not be placed between an adjective (warm-blooded) and noun (animals), so (A) and (B) can both be eliminated. (D) is also incorrect because actively warm-blooded does not make sense. Dinosaurs were not warm-blooded in an active way, as this answer would imply; rather, they were creatures that were both active and warm-blooded. Two separate adjectives are therefore required. That leaves (C), which correctly uses a comma to separate the adjectives active and warm-blooded.

12/3/24

The current reality of smart cities is that there aren’t any. At the end of the day, most so-called smart cities are just cities with a few or several standout smart projects. Such projects can take shape in a variety of ways. In Pittsburgh, the Pennsylvania Department of Transportation is piloting a $30 million smart-signal system that utilizes adaptive traffic signals to read traffic conditions and make adjustments to keep traffic flowing. Kansas City invested nearly $15 million in a smart lighting project that will install 200 lights along its new streetcar line. The lights have built-in sensors and cameras that detect the presence of people and can turn off when no one is around to save 20–30 percent in electricity costs. Both efforts represent the potential of smart city technology, but they certainly do not represent the networked, end-to-end planning of an entire smart city.

The references to “adaptive traffic signals” and “a smart lighting project” primarily serve to

A. celebrate the power of technological innovation.
B. call attention to recent developments in urban design.
C. illustrate the exceptional nature of certain projects.
D. emphasize the growing popularity of smart city technologies.

The key to answering this question is to recognize that it’s a purpose or “function” question. It is not asking you to focus on what the passage literally says about “adaptive traffic signals” and “a smart lighting project.” Rather, it is asking you what main idea those references are used to support. As a result, you must focus on the beginning of the passage, where the main idea is most likely to be located. The second sentence states that most so-called smart cities are just cities with a few or several standout smart projects. In the following portion of the passage, traffic signals and lighting project are then cited as examples (= illustrations) of standout (= exceptional) smart projects (= certain projects). That makes the answer (C).

12/2/24

Tipping as a phenomenon has long fascinated economists: paying extra, even though we are not legally required to do so, seems to go against our own best interest.

A. NO CHANGE
B. economists paying extra –
C. economists, paying extra,
D. economists; paying extra

The original version correctly uses a colon to introduce an explanation (why economists are fascinated by tipping) and places a comma after extra to mark the beginning of a non-essential clause (even though we are not legally required to do so). You can tell that the clause is non-essential because the sentence still makes sense when it is crossed out: paying extra…seems to go against our own best interest.

(B) is incorrect because a dash can be used interchangeably with a colon, but here the dash is placed in an illogical spot: even though we are not legally required to do so, seems to go against our own best interest does not make sense as an explanation.

Be careful with (D): although the semicolon is correctly used to separate two sentences, the comma after extra is required to signal the start of the non-essential clause. Because no comma is present, this answer cannot be correct.

12/1/24

Over the last several decades, research has effectively disproved the claim that coffee is harmful to health. In fact, data suggest that coffee may offer some health benefits. In comparison to non-coffee drinkers, for example, drinking about three cups of coffee a day appeared to reduce the risk of heart problems.

A. NO CHANGE
B. about three cups of coffee a day can reduce people’s risk of heart problems.
C. heart problems are reduced in people who drink about three cups of coffee daily.
D. people who drink about three cups of coffee a day have a reduced risk of heart problems.

The original version incorrectly compares non-coffee drinkers (people) to drinking about three cups of coffee a day (action). In order to be correct, the sentence must compare people to people. (D) is the only option that does so, making it the answer. All of the other information in the answer choices is irrelevant.

Explanation