Explanations December -

12/31/23

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).

12/30/23

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.

12/29/23

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.

12/28/23

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.

12/27/23

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.

12/26/23

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…

12/25/23

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.

12/24/23

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.

12/23/23

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.

12/22/23

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.

12/21/23

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.

12/20/23

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.

12/19/23

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.

12/18/23

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.

12/17/23

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.

12/16/23

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.

12/15/23

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.

12/14/23

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.

12/13/23

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.

12/12/23

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.

12/11/23

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.

12/10/23

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.

12/9/23

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.

12/8/23

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.

12/7/23

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.”

12/6/23

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.

12/5/23

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.

12/4/23

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.

12/3/23

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).

12/2/23

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.

12/1/23

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.

Explanations December