Given that most people imagine robots as large, autonomous machines covered in blinking lights and guided by artificial intelligence, but the reality is that robots come in all sorts of forms and sizes.
A. NO CHANGE
B. Although most people
C. Insofar as most people
D. Most people
As a rule, a sentence cannot contain two clauses in a row that begin with transitions. Because the second clause begins with a transition (but), the first clause cannot begin with one as well. (D) is the only option that does not begin the first clause with a transition, and so it is the only possible answer.
Note that it is irrelevant whether you find the particular transitions here confusing (given that means “because” and insofar as means “to the extent that”): the only thing that matters is the grammatical structure of the sentence. The transitions are wrong because they do not belong at all, not because of their meanings.
Every culture has its own unique music that is unlike the music of any other culture, but some researchers have hypothesized that certain features and patterns hidden among the notes and rhythms are common to all cultures. Until now, however, evidence for these potentially universal features has been lacking.
A. NO CHANGE
B. that is like no other culture’s music
C. that is shared by no other culture
D. DELETE the underlined portion
The non-underlined portion of the sentence states that every culture has its own unique music. By definition, music that is unique to a culture is unlike any other culture’s music, or not shared by any other culture, so it is unnecessary to provide that information in the sentence. As a result, (A), (B), and (C) are all redundant and can be eliminated; (D) correctly deletes the unnecessary information.
No matter their design, all skates work by the same common principle: as the blade travels over ice, it melts a thin layer of water that allows the skater to glide. However, the speed and function of a skate depends on the shape and size of the blade and boot. Blade thickness and boot sturdiness affect speed, and a long blade makes for a faster skate.
A. NO CHANGE
C. has depended
D. would depend
Although the answers contain verbs in different tenses, a pattern that initially suggests that the question is testing tense, it’s also a subject-verb agreement question. The real giveaway is the fact (A) and (C) contain singular verb (depends, has), whereas (B) contains a plural verb (depend). That means you need to start by determining the subject of the verb. Be very careful here: if you focus on the information right before the verb (the word skate, or even the phrase function of a skate), you’re likely to think that the subject is singular and that (A) is correct. In reality, however, the sentence contains a compound subject, which is plural: speed and function. The phrase of a skate is a prepositional phrase that is inserted between subject and verb to distract from the disagreement. As a result, a plural verb (depend) is required. Although would depend fits after either a singular or plural subject and is grammatically correct on its own, (D) is incorrect because all of the other verbs are in the present tense (work, melts, allows, etc.), and there is no reason to switch tense here. That makes (B) the answer.
There are a handful of substances clearly demonstrated to cause sleep. Including a molecule called adenosine, which appears to build up in certain parts of the brains of waking animals and drain away during slumber.
A. NO CHANGE
B. sleep, including a molecule called adenosine, which
C. sleep, including a molecule called adenosine; which
D. sleep, they include a molecule called adenosine, which
(A) is incorrect because the statement before the period is a sentence, but the statement after is a fragment: it contains two clauses, neither of which can stand on its own as a sentence. The first lacks a subject and a verb, and the second begins with which, a word that cannot be used to start a sentence (other than a question). (C) is incorrect for that reason as well: Because which cannot begin a sentence, it should not be placed after a semicolon, which is grammatically identical to a period. Instead, it must follow a comma. (D) is incorrect because it creates a comma splice — two sentences divided by only a comma, an error signaled by the construction comma + they. (B) correctly places a comma before which and avoids the comma splice by using an -ING word (including) rather than comma + they to join the parts of the sentence.
As the son of an electrical worker, Einstein learned about physics not only by reading but also by observing firsthand the technology they’re applications could produce.
A. NO CHANGE
Start by determining the noun to which the underlined pronoun refers: the technology produced by the applications of what? Logically, the word in question must refer to physics. Don’t be fooled by the fact that this word ends in -s — it’s a singular noun that just happens to end with that letter. (In fact, physics doesn’t really have a plural form, at least not one that’s used under normal circumstances). As a result, a singular pronoun is required. They and their are plural, so (A) and (B) can be eliminated. It’s = it is, and you would not say …by observing firsthand the technology it is applications could produce, so (D) can be eliminated. That leaves (C), which correctly provides the singular possessive, its. (Its applications = the applications of physics.)
The brain’s default network consists of a series of regions that are activated when people engage in spontaneous thinking, such as daydreaming and imagining. This network may play a key role in idea generation or brainstorming—thinking of several possible solutions to a problem.
Which of the following is the LEAST acceptable alternative to the underlined word?
This is a “LEAST” question, so the right answer must be a word that is NOT acceptable as a general synonym for activate. Mobilized, stimulated, and animated are all acceptable ways to describe regions of the brain that are turned on, or that go into action, when people begin to engage in spontaneous thinking. Inspired does not fit because only a person can be inspired — it is idiomatically inappropriate to use this verb to describe the effects of thought on physical structures in the brain. (D) is, therefore, the LEAST acceptable alternative to the underlined word, making it correct.
Recent findings indicate that individuals who demonstrate high levels of creativity are better able to engage brain systems that don’t typically work together. Interestingly, the results are consistent with recent MRI studies of jazz musicians improvising melodies, poets writing new lines of poetry, and illustrators sketching ideas for a book cover.
Which option provides an example most similar to the examples already in the sentence?
A. NO CHANGE
B. scientists conducting a laboratory experiment.
C. lawyers doing research for an important case.
D. chefs preparing a complex recipe.
The first two examples in the sentence describe artists (jazz musicians, poets) engaged in creative acts. In addition, the first sentence refers to individuals who demonstrate high levels of creativity. As a result, the third example must describe an artist engaged in some type of creative act as well. (B), (C), and (D) all refer to professionals performing challenging work, but scientists, lawyers, and chefs are not artists. Illustrators are, however, artists, and sketching ideas for a book cover is a creative act, so (A) fits most logically with the previous two examples.
The complexity of understanding even simple speech is fully appreciated by computer scientists, who since the 1950s have struggled to create a machine capable to respond to human language.
A. NO CHANGE
B. in responding
C. of responding
The correct idiom is capable of responding. Prepositions beside of and the infinitive (to respond) are incorrect, eliminating (A) and (B). It is also unacceptable not to include a preposition, as in (D). That makes the answer (C).
The sandhills of Nebraska form the largest sand dunes in North America. These dunes spread for more than 20,000 square miles, covering more than a quarter of the state.
What is the best way to combine the sentences at the underlined portion?
A. North America, and these dunes spread
B. North America: they spread
C. North America; and spreading
D. North America, but they spread
(A) is grammatically acceptable, but it is also longer than the other answers, and the repetition of the word dunes is awkward. (C) is incorrect because a complete sentence must appear on either sentence of a semicolon, but and spreading for more than 20,000 square miles, covering more than a quarter of the state is not a sentence. (D) is incorrect because but is used to signal a contrast, and there is no contradiction between the fact that Nebraska’s sandhills form the largest sand dunes in North America and the fact that they spread for 20,000 square miles. Rather, those are similar ideas. (B) is correct because the colon signals that the second part of the sentence will expand on or explain the first, and it appropriately places a complete, standalone sentence (The sandhills of Nebraska form the largest sand dunes in North America) before the colon.
Visit the grocery store on an empty stomach, and you will probably come home with a few things, you did not plan to buy. But hunger pangs are not the only culprit behind impulse purchases. The location of store displays also influences shopping choices—and may make or break some healthy eating habits.
A. NO CHANGE
B. things, that you
C. things that, you
D. things you
The key to answering this question is to recognize that the underlined portion can correctly be written with or without that: …you will probably come home with a few things that you did not plan to buy, OR …you will probably come home with a few things you did not plan to buy. The rule is that when the word that is optional and does not appear, no comma should be used to replace it. And as a general rule, no comma should be used before or after that either. As a result, no punctuation is necessary, making the answer (D).
Some studies show even relatively mild levels of hypoxia (oxygen deficiency) can prevent people from thinking clearly. At oxygen levels equivalent to altitudes above 12,000 feet, he or she may begin to show measurable changes in memory and decision-making abilities. This is why aviation regulations require that pilots wear supplementary oxygen masks if the cabin air pressure is greater than that found at 12,500 feet.
A. NO CHANGE
All of the answers work grammatically if the sentence is considered in isolation, but only one option fits in context. The only noun in the passage that the underlined pronoun can logically refer to is people — note that you need to back up a sentence in order to identify it. People is plural, so the correct pronoun is they, making (C) the answer. In (A), he or she is used only to refer to singular nouns. (B) is incorrect because one must be paired with one, and (D) is incorrect because you must be paired with you.
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
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: Snakebites 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.
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 knowledge, 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.
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
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).
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.
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
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.”
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.
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.
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 Weem’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.
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 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.
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.
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
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.
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.
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
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.
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.
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 size 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.
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
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.
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
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.
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
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.
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.
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
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.
And for additional practice, Critical Reader Books include hundreds of practice questions and explanations.