Explanation -

5/30/25

It wasn’t that long ago that putting food in liquid nitrogen was something you’d only see in a high school science class, but it’s also becoming a mainstay of modernist cooking. It’s odorless, tasteless, and harmless because it’s so cold (–320.44°F to be exact), it boils at room temperature and evaporates out of your food as it rapidly chills it.

A. NO CHANGE
B. tasteless, and harmless, and because
C. tasteless and harmless, because
D. tasteless, harmless and because,

Be very careful with (A): even though the first part of the sentence makes sense grammatically, the comma after the close-parenthesis actually creates a comma splice — two complete sentences separated by only a comma. (Sentence 1: It’s odorless, tasteless, and harmless because it’s so cold (–320.44°F to be exact); Sentence 2: it boils at room temperature and evaporates out of your food as it rapidly chills it.) As a result, this answer can be eliminated. (C) creates the same error; this option merely places an additional comma before because. Note that the lack of a comma after tasteless is a distraction; the comma before the last item in a list is optional. (D) is incorrect because no comma should ever be placed after a subordinating conjunction (because) — that construction automatically eliminates this answer from consideration. (B) is correct because the comma + and = period, and the sentence can be logically divided after harmless: It’s odorless, tasteless, and harmless. Because it’s so cold (–320.44°F to be exact), it boils at room temperature and evaporates out of your food as it rapidly chills it.

5/29/25

Although it may sometimes get overlooked in the hustle and bustle of the daily commute, New York City’s subway stations are packed with art. Over the years, stations have become home to all sorts of works like mosaics of peering eyes or disarmingly cute bronze sculptures. According to the Metropolitan Transit Authority (MTA), subway art has been a part of the transit system’s lifeblood since its earliest days.

A. NO CHANGE
B. disarmingly, cute bronze sculptures.
C. disarmingly cute, bronze, sculptures.
D. disarmingly cute, bronze sculptures.

(B) is incorrect because no comma should be placed between an adverb (disarmingly) and an adjective it modifies (cute). (C) can be easily eliminated as well because no comma should be placed between an adjective (bronze) and the noun it modifies (sculptures). (D) is trickier, though, because a comma can sometimes be placed between two adjectives. In this case, however, the comma between cute and bronze is unnecessary. The rule is that no comma is needed when one adjective modifies the other, as is the case here (cute modifies bronze sculptures). In addition, a comma should be used when and can be inserted between the adjectives, or when the order of the adjectives can be reversed, neither of which is true here (it does not sound right to say disarmingly cute and bronze sculptures or bronze, disarmingly cute sculptures). Because no commas are needed, (A) is correct.

5/28/25

Lions and great white sharks may boast the most famous jaws in the animal kingdom—but theirs are nowhere near the fastest. That honor belongs to Odontomachus bauri, a tiny ant whose jaws can snap shut at a remarkable 145 miles per hour. The ant’s quick bite also does double-duty as an escape mechanism. When faced with a larger nest intruder, an ant may use its jaws to strike the invader, simultaneously flinging itself 8 or 9 inches away (a maneuver known as the “bouncer defense”). Therefore, it may snap its jaws against the ground, propelling itself into the air and out of the way of such dangers as an anteater’s tongue (a move known as an “escape jump”).

A. NO CHANGE
B. For example,
C. Alternatively,
D. Meanwhile,

To answer this question, you must consider the role of the sentence begun by the transition within the passage as a whole. You should also cross out (or try to ignore) the original transition so that you do not get distracted by it and try to find a relationship that is not actually present. If you back up a few couple of sentences, you can see that the passage is discussing Odontomachus bauri’s ability to use its jaws in order to escape from predators. The previous sentence describes one way that the ant can accomplish this feat, namely by using its jaws to strike while flinging itself away. The key to answering this question is to recognize that the last sentence — the sentence begun by the transition — describes a second, or different, method of escape (“the escape jump”) used by this ant. It does not describe a consequence or an example of the first method, eliminating (A) and (B). (D) can also be eliminated because placing meanwhile at the beginning of the last sentence would imply that the ant was using the two different defenses simultaneously, which would be physically impossible. Alternatively accurately conveys that the final sentence is describing an alternate method of defense, making the answer (C).

5/27/25

Until 1877, all rapid long-distance communication depended upon the telegraph. However, that year saw the development of a rival technology: the telephone. In 1879, patent litigation between Western Union, which controlled the telegraph industry, and the infant telephone system ended in an agreement largely that separated the two services.

The best placement for the underlined word is

A. where it is now.
B. after the word that.
C. after the word two.
D. after the word services.

Largely is an adverb and thus can only be used to modify a verb. Because modifiers should be placed next to the words they modify, largely should come either before or after a verb. (B) is the only option that places this word next to a verb: when it is inserted after that, it is also placed before the verb separated. This is also the only position in the sentence that creates a logical meaning: how were the two services separated? largely.

5/26/25

Richard Sylvester of the University of Western Australia has associated the mysterious disappearances of ships in the Bermuda triangle with the Sargasso Sea. Vast amounts of seaweeds accumulate at its center, where powerful currents slowly circulate, creating a huge whirlpool. That whirlpool, which extends into the area of the Bermuda triangle, creates smaller whirlpools, strong enough to cause mini-cyclones capable of rotating a ship and dragging it inside.

A. NO CHANGE
B. whirlpools strong enough
C. whirlpools strong enough,
D. whirlpools are strong enough

The key to answering this question is to recognize that the underlined phrase can be written two ways: …creates smaller whirlpools that are strong enough to cause mini-cyclones or …creates smaller whirlpools strong enough to cause mini-cyclones. When that is optional and does not appear, no comma should be used in its place. That eliminates (A) and makes (B) correct. (C) does not fit because when this answer is plugged into the passage, the comma after enough wrongly places a comma before a preposition (to). (D) is incorrect as well because using only a verb (are) without that in front of it creates a nonsense construction: That whirlpool…creates smaller whirlpools are strong enough to cause mini-cyclones capable of rotating a ship and dragging it inside.

5/25/25

A comprehensive 2016 study by the National Academy of Sciences concluded that genetically engineered crops are just as safe to eat as their non-genetically engineered counterparts, yet in one survey, more than a quarter of consumers reported that they avoid to purchase them.

A. NO CHANGE
B. of purchasing
C. in purchasing
D. purchasing

The correct idiom is avoid + -ing (avoid purchasing). Either the infinitive or the use of a preposition before the -ing word is incorrect. That makes (D) the only possible answer.

5/24/25

Life as we know it requires liquid water, which can exist on planets with a surface temperature and a mass similar to the Earth’s. Surface heating is also needed to prevent water from freezing and becoming ice, and Earth-like gravity is required to retain an atmosphere—an essential feature since ice turns directly into gas in the absence of an external atmospheric pressure.

A. NO CHANGE
B. freezing and turning into ice
C. freezing so that it becomes ice
D. freezing,

By definition, water that freezes becomes ice, so it is sufficient to refer to water’s freezing. All of the answers except (D) contain redundancies. Shortcut: shorter is better. You can make a very educated guess that (D) is correct simply by looking at the lengths of the answer choices.

5/23/25

In pumping her “Wonderful Hair Grower” door-to-door, at club gatherings, and eventually through a mail-order catalog, Sarah Walker—who eventually decided to promote herself professionally under the name, Madame C.J. Walker, proved to be a marketing magician who sold her customers more than mere hair products. She offered them a lifestyle, a concept of total hygiene and beauty that in her mind would bolster their pride.

A. NO CHANGE
B. name Madame C.J. Walker—
C. name, Madame C.J. Walker
D. name Madame C.J. Walker,

If you read the entire sentence in which the underlined portion appears, you can notice that it contains a dash after Sarah Walker. That dash signals the beginning of a non-essential clause whose end must be marked with a dash as well. As a result, (B) is the only possible answer; the question of whether a comma belongs before the name is only a distraction here. To test out (B), you can cross out the information between the dashes: In pumping her “Wonderful Hair Grower” door-to-door, at club gatherings, and eventually through a mail-order catalog, Sarah Walker…proved to be a marketing magician who sold her customers more than mere hair products. Because the remaining sentence makes sense, the clause is non-essential, and the same form of punctuation must be used to signal its beginning and end.

5/22/25

In 1850, Joel Houghton registered a patent for the first mechanical dishwasher in the United States. The device was made of wood and was cranked by hand while water sprayed onto the dishes, and they were both slow and unreliable. Fifteen years later, another patent was granted to L.A. Alexander. It was similar to the first but featured a hand-cranked rack system. Like Houghton’s, this contraption was neither practical nor widely accepted.

A. NO CHANGE
B. it was
C. those were
D. DELETE the underlined portion.

The only plural noun in the sentence that contains the underlined portion is dishes, and it does not make any sense to say that dishes were slow and unreliable. They and those are plural, so (A) and (C) can be eliminated. The sentence also does not make sense if the underlined pronoun is removed entirely, so (D) can be eliminated as well. Logically, the underlined pronoun refers to the device (i.e., the first mechanical dishwasher), which is singular, so a singular pronoun (it) is required. That makes (B) correct.

5/21/25

Hedy Lamarr and her co-inventor, the composer George Anthiel, figured out how to use the mechanics of the player piano to create the earliest version of the “frequency-hopping spread-spectrum” system. A method that protects radio communications by switching frequencies in a preprogrammed pattern.

A. NO CHANGE
B. system a method that
C. system, a method that
D. system, a method

(A) is incorrect because the statement beginning with A method is not a complete sentence: the verb protects “belongs” to the pronoun that, and the subject of the sentence (A method) lacks a verb. (B) is incorrect because some type of punctuation is needed to signal that a new clause is beginning after system — without it, a run-on is created. (D) is also incorrect because eliminating that creates a nonsense construction; it also makes the clause after the comma independent, creating a comma splice. (C) correctly uses a comma to separate an independent clause (Hedy Lamarr and her co-inventor, the composer George Anthiel, figured out how to use the mechanics of the player piano to create the earliest version of the “frequency-hopping spread-spectrum” system) from a dependent clause (a method that protects radio communications by switching frequencies in a preprogrammed pattern) and retains the necessary word that.

5/20/25

In Washington, D.C., viewing the cherry blossoms is a time-honored tradition that dates back to 1912. At that time, Tokyo presented 3,020 cherry trees to the United States in an act of friendship. The Cherry Blossom Festival was launched in 1935 to commemorate the springtime occasion, and it is still celebrated today.

What is the most effective way to combine the two sentences at the underlined portion?

A. that dates back to 1912, when Tokyo presented
B. dating back to 1912, and that was a time when Tokyo presented
C. that dates back to 1912, and Tokyo then presenting
D. that had dated back to 1912, which is when Tokyo presented

(A) is correct because it joins the two sentences most cleanly and concisely by replacing the phrase at that time with when alone. (B) is incorrect because the phrase and that was a time when Tokyo presented makes this answer unnecessarily wordy. The phrase which is when Tokyo presented makes (D) wrong for the same reason. (C) can also be eliminated because the gerund presenting creates a fragment — the clause after the comma lacks a main verb.

5/19/25

Raising mice in captivity has been traced back to the seventeenth century, when collectors in Japan selected for traits such as coat color or unique behaviors. Two centuries later, “fancy” mice experienced a gust in popularity in Britain and in the United States, with people keeping them for pets and breeding interesting specimens for mouse shows.

A. NO CHANGE
B. surge
C. race
D. stream

To say that something experienced as “surge” in popularity is to say that it experienced a sharp increase in popularity. None of the other answers can be used idiomatically to have this meaning. (B) is thus correct.

5/18/25

The Apollo 11 mission became famous for allowing astronauts to land on the lunar surface in 1969. However, the flight of Apollo 8, which sent the first crew to orbit the moon seven months earlier, was in some ways even riskier, its success more surprising.

A. NO CHANGE
B. its’
C. they’re
D. their

The subject of the sentence is the flight of Apollo 8, which is singular. As a result, the underlined pronoun must be singular as well. (Don’t get distracted by the plural noun astronauts in the previous sentence — the sentence in which the underlined noun appears is clearly about the Apollo 8 mission.) They’re and their are both forms of they (plural), eliminating (C) and (D), and (B) can be eliminated because its’ does not exist. That leaves (A), which correctly provides the singular possessive, its. Its success = the sucess of Apollo 8.

5/17/25

When scientists cracked open the Murchison meteorite, which fell in Australia in 1969, and scraped the material on the inside, they discovered that it was chock-full of carbon and organic materials. It also had an odd smell, reminiscent of the New York City subway—metallic, with musty and bitter hints.

A. NO CHANGE
B. 1969 and scraped the material on the inside they
C. 1969, scraped the material on the inside, they
D. 1969, and scraped the material on the inside—they

If you read the sentence from the beginning, you’ll notice that it contains comma + which, indicating a non-essential clause. To simplify the sentence, cross out the clause: When scientists cracked open the Murchison meteorite…and scraped the material on the inside, they discovered that it was chock-full of carbon and organic materials. That makes perfect sense, suggesting that (A) is correct. If you’re not sure, though, you can check the other answers. (B) is incorrect because a comma must be placed after 1969 to mark the end of the non-essential clause. (C) does not work because without the word and, the sentence no longer makes sense when the non-essential clause is removed: When scientists cracked open the Murchison meteorite…scraped the material on the inside, they discovered that it was chock-full of carbon and organic materials. (D) is incorrect because it is incorrect to use a dash rather than a comma before they. It does not mark the end of a non-essential clause begun by another dash (don’t get distracted by the unrelated dash after subway, later in the passage), nor is it used stylistically, to create a dramatic pause. In case of the latter, a dash must be preceded by a complete, standalone sentence, and When scientists cracked open the Murchison meteorite, which fell in Australia in 1969, and scraped the material on the inside cannot stand on its own as a complete thought. That leaves (A), which appropriately punctuates the underlined portion.

5/16/25

As the United States stood on the brink of a Second World War, the push for aeronautical advancement grew ever greater, spurring an insatiable demand for mathematicians. Ushered into the Langley Memorial Aeronautical Laboratory in 1935 to shoulder the burden of number crunching, engineers were freed from hand calculations in the decades before the digital age by dozens of women acting as human “computers.”

A. NO CHANGE
B. in the decades before the digital age, dozens of women acting as human “computers” freed engineers from hand calculations.
C. dozens of women acting as “human computers” freed engineers from hand calculations in the decades before the digital age.
D. hand calculations were freed from engineers by dozens of women acting as human “computers” in the decades before the digital age.

Who was ushered into the Langley Memorial Aeronautical Laboratory in 1935? Dozens of women. It would not make sense for the introductory phrase to describe engineers: this group could not be asked to shoulder the burden of number crunching and be freed from hand calculations simultaneously. So dozens of women, the subject, must be placed at the beginning of the underlined portion; otherwise, a dangling modifier is created. (C) is the only option to contain the correct construction, so it is the only possible answer.

5/15/25

When Paige Embry, author of Our Native Bees: North America’s Endangered Pollinators and the Fight to Save Them, learned that bees extract pollen from flowers by shaking them, she embarked on a reporting journey to document the lives of North America’s 4,000 wild native pollinators. Some secrete silk, she discovered, while others shave fuzzy plants to build plush pillows for their eggs. Still others nest in rose stems, cow patties, or snail shells.

A. NO CHANGE
B. them. She embarked
C. them, and she embarked
D. them, she embarked,

The sentence in which the underlined portion appears is quite long, but you can simplify the sentence by crossing out the non-essential clause: When Paige Embry…learned that bees extract pollen from flowers by shaking them, she embarked on a reporting journey to document the lives of North America’s 4,000 wild native pollinators. Now the basic structure of the sentence is clear: it contains a dependent clause (When Paige Embry, author of Our Native Bees: North America’s Endangered Pollinators and the Fight to Save Them, learned that bees extract pollen from flowers by shaking them) followed by an independent clause (she embarked on a reporting journey to document the lives of North America’s 4,000 wild native pollinators). When a dependent clause comes before an independent clause, a comma should be placed between them. That eliminates (B). (C) can be eliminated as well because comma + and is grammatically identical to a semicolon. (D) correctly places a comma after them, but the second comma, after embarked, inappropriately places a comma before a preposition (on) when the answer is plugged back into the sentence. (A) correctly places a single comma after them, dividing the dependent clause from the independent clause.

5/14/25

In recent years, scientists have become increasingly aware that plants thrive through cooperation rather than competition. For example, oaks that are subjected to drought conditions have been shown to provide nutrition to their beneficial partners by transferring water from their tap roots up through their root systems to associated fungal networks, nourishing these beneficial partners. In fact, some researchers believe that such networks are the principal way that plants extract nutrients from the soil.

A. NO CHANGE
B. providing nourishment for these beneficial partners.
C. sustaining these beneficial partners.
D. DELETE the underlined portion (replacing the comma after networks with a period).

The sentence in which the underlined portion appears already contains the phrase provide nutrition to their beneficial partners, and the underlined section repeats the information almost verbatim. As a result, it is redundant to include that statement or any variation on it at the end of the sentence. The best option is to delete it entirely, making (D) correct.

5/13/25

When I was a child growing up on the Eastern Shore of Maryland, crossing a big bridge meant facing unexpected challenges. The majestic Chesapeake Bay Bridge was my family’s main route off of the rural shore and towards “real cities,” where we could walk among crowds and shop in stores unlike anything we had at home. But these trips were also journeys in themselves— a chance to spot bottlenose dolphins and peregrine falcons and to see both our home and our destination from a new perspective.

Which choice best introduces the topic of the paragraph?

A. NO CHANGE
B. taking a step toward independence.
C. entering a portal to a new world.
D. returning to my roots.

Because this question asks you to identify the option that “best introduces the topic of the paragraph,” you must start by determining that topic — and to do that, you must ignore the first sentence and read the rest of the paragraph. What does it focus on? The fact that the writer and his or her family could experience things unlike anything we had at home, and see things from a new perspective. The correct answer must correspond to those ideas. The paragraph says nothing about challenges, unexpected or otherwise, eliminating (A), nor does it say anything about the narrator’s independence, eliminating (B). (D) is incorrect because the passage gives no indication that the narrator’s family was returning to its roots. Rather, the focus is on the newness of the world beyond the Chesapeake Bay Bridge. That corresponds directly to (C).

5/12/25

Although it is estimated that 10 meteorites come crashing to Earth from outer space every day, researchers only discover a few of these rocks each year. They are easiest to spot when they fall on relatively stable geographic environments, making it unnecessary for search teams to use metal detectors like the Arizona desert.

A. NO CHANGE
B. environments that make it unnecessary for search teams to use metal detectors like the Arizona desert.
C. environments like the Arizona desert, making it unnecessary for search teams to use metal detectors.
D. environments like metal detectors that make it unnecessary for search teams in the Arizona desert.

The original version creates a misplaced modifier: read literally, the phrase to use metal detectors like the Arizona desert implies that the Arizona desert is a metal detector — clearly a ridiculous meaning. (B) creates the same error; the replacement of making it with that make it does not address the real problem in the sentence. (D) creates a different misplaced modifier: the phrase environments like metal detectors illogically implies that metal detectors are environments. (C) is correct because it makes clear that the Arizona desert is an environment.

5/11/25

In 1997, David Perry founded Indigo Ag, a company dedicated to commercializing microorganisms that help plants grow. Indigo Ag’s scientists have identified a variety of microbes that confer resistance to drought, are developing others that reduce the need for chemical fertilizers and pesticides in five important crops: corn, rice, soybeans, cotton, and wheat.

A. NO CHANGE
B. scientists identify
C. scientists, having identified
D. scientists identified

At first glance, the different tenses in the answer choices (have identified, identify, identified) might suggest that this question is testing tense, but in fact it is doing something very different. To determine the answer, you must back up and consider the sentence as a whole — the underlined portion alone does not provide sufficient information to answer the question. If you read the entire sentence, you can notice that the comma alone after drought does not make sense. It would be acceptable to say Indigo Ag’s scientists have identified a variety of microbes that confer resistance to drought and are developing others that reduce the need for chemical fertilizer, but the comma by itself after drought is not correct. Because there is no way to change the end of the sentence, the underlined portion must be changed instead.

The key is to recognize that the comma after drought can signal the end of a non-essential clause. As a result, the underlined portion must signal the beginning of a non-essential clause. This construction makes sense because when the non-essential information is crossed out, the sentence still makes grammatical sense: Indigo Ag’s scientists…are developing others that reduce the need for chemical fertilizers and pesticides in five important crops... A non-essential clause must be set off by a comma and cannot begin with a verb, and so the correct answer must contain those elements. That makes (C) the only possibility.

5/10/25

In the past few years, governments have begun to see automation as the key to better urban futures. Many cities are becoming test-beds for experiments with robots in social spaces, where robots have both a practical purpose (for which they are programmed) and a symbolic role (to demonstrate good city governance). Whether through autonomous cars, automated pharmacists, service robots in local stores, or autonomous drones delivering parcels, cities are being automated at a steady pace.

Which choice provides an example that is most similar to the other example in the sentence?

A. NO CHANGE
B. (to facilitate everyday life)
C. (they come in many shapes and sizes)
D. (and are becoming ever more intelligent)

By directing you to look at the “other example in the sentence,” the question itself provides an important clue. Start by looking at the construction of the other example: the symbolic role of robots is defined in parentheses, and the definition begins with an infinitive (to facilitate). The first example must match: the information within the parentheses must define the practical purpose of robots and begin with an infinitive. All of the answers could apply to robots in general, but only (B) begins with an infinitive (to facilitate) and is truly consistent with the idea of a practical purpose. As a result, it is correct.

5/9/25

Today, humans can live in space for months at a time, and some space travelers are lucky enough to visit the realm of microgravity more than once. Repeat trips into space teach astronauts not only to survive in a hostile and alien environment but also adjusting to life back on Earth.

A. NO CHANGE
B. they adjust
C. adjusted
D. to adjust

To answer this question, you must consider the sentence as a whole. The fact that it contains a word pair (not only…but also) is a clue that the question is testing parallel structure: as a rule, the construction on one side of a word pair must match the construction on the other side. Not only is followed by an infinitive (to survive), so but also must be followed by an infinitive (to adjust) as well. That makes (D) the only option.

5/8/25

The “Green Revolution”—championed by American agronomist Norman Borlaug, who was awarded the Nobel Peace Prize in 1970 for his work—led farmers to: increase their use of chemical fertilizers, adopt high-yielding crop varieties, and improve their irrigation practices and technologies. Today, those practices are firmly entrenched aspects of industrial agriculture.

A. NO CHANGE
B. to increase their use of chemical fertilizers;
C. to increase their use of chemical fertilizers,
D. to increase their use, of chemical fertilizers

Although the sentence contains a list, it is incorrect to place a colon after to. This type of punctuation must follow a complete, standalone sentence, and The “Green Revolution”—championed by American agronomist Norman Borlaug, who was awarded the Nobel Peace Prize in 1970 for his work—led farmers to clearly does not express a complete thought. That eliminates (A). (B) is incorrect because the other two items in the list are set off by commas rather than semicolons, and the punctuation between items must be consistent. (D) is incorrect because this answer places a comma before a preposition (of) and eliminates the punctuation between the first and second items in the list. (C) is correct because this answer maintains consistency with the rest of the list by placing a comma after the first item.

5/7/25

In the never-ending symphony of the sea, there’s a standout among the percussive pings of bottlenose dolphins and the plaintive calls of humpback whales. Recordings of bowhead whales show that these mammals sing intricate yet varied songs—they’re more like jazz musicians than Beethoven or Bach.

A. NO CHANGE
B. intricate, yet varied
C. intricate yet, varied
D. intricate yet varied,

As a rule, when two adjectives (intricate, varied) are separated by but or yet, no comma should be used. That eliminates (B) and (C). (D) eliminates the comma between the adjectives themselves, but the comma after varied creates a new problem: the comma is incorrectly placed between an adjective (varied) and the noun it modifies (songs). (A) is correct because no punctuation is necessary in the underlined section.

5/6/25

The largest pyramid, built for the Pharaoh Khufu around 2530 B.C. and intended in lasting an eternity, was until fairly recently the largest building on the planet. To raise it, laborers moved six-and-a-half million tons of stone—some in blocks as large as nine tons—into position using nothing but wood and rope.

A. NO CHANGE
B. on lasting
C. for lasting
D. to last

The correct idiom is something is intended to do x; it is incorrect to use the gerund (lasting), regardless of the preposition that precedes it. (D) provides the infinitive (to last), so it is the only possible answer.

5/5/25

Numerous factors—from changes in air temperature to the tug of nearby storms—can affect a tornado’s development. Unlike hurricanes, which can be spotted days off shore, tornadoes develop over the course of hours or minutes, which makes taking on-the-ground measurements even more challenging.

A. NO CHANGE
B. affect a tornadoes development.
C. effect a tornado’s development.
D. effect a tornadoes development.

Affect is a verb, whereas effect is a noun. Because a verb must follow can, affect is the correct version, eliminating (C) and (D). (B) can be eliminated as well because tornado must be possessive rather than plural: tornado’s development = development of a tornado. Tornodoes is the plural form (note the lack of an apostrophe). The original version provides the correct form of both words, making (A) correct.

5/4/25

The cognitive scientist Rafael Núñez of the University of California at San Diego doesn’t buy the conventional wisdom that people have a naturally innate capacity for understanding numbers. Rather, he thinks that “number sense” is a product of culture, like writing and architecture.

A. NO CHANGE
B. a natural and innate
C. a natural, innate
D. an innate

Natural and innate (inborn) have the same basic meaning, so it is redundant to use both words. Only one is sufficient, making (D) correct.

5/3/25

The emperors of the Tang Dynasty (618 – 907 AD) are believed to have been the first to eat a frozen, milky confection. This early version of ice cream was made with cow, goat, or buffalo milk that was heated with flour. Camphor, an aromatic substance harvested from evergreen trees, was added to enhance the texture and flavor. Subsequently, the mixture was placed into metal tubes and lowered into an icy pool until frozen.

A. NO CHANGE
B. Nevertheless,
C. Thus,
D. Despite this,

The easiest way to answer this question is to recognize that the passage is describing the steps used to make an early version of ice cream. Logically, the mixture must have been frozen after all the ingredients were added — in other words, the mixture was heated and had camphor added to it, and afterward it was placed into metal tubes and lowered into an icy pool. Subsequently is a transition word meaning “then” or “after,” so (A) is correct. There is no contradiction between the sentence begun by the transition and the previous sentence, so (B) and (D) do not fit. (C) does not make sense either because the freezing of the mixture did not directly result from the addition of all the ingredients; this step merely took place at a later time.

5/2/25

Despite the economic promises touted by supporters of the Golden Gate Bridge, the project met fierce resistance from an array of business and civic leaders. Not only would the bridge impede the shipping industry and mar the bay’s natural beauty, they argued, it wouldn’t survive a trembler like the San Francisco Earthquake that crippled the city in 1906.

A. NO CHANGE
B. it also won’t survive
C. and it also wouldn’t survive
D. but it also wouldn’t survive

To answer this question, you must consider the beginning of the sentence — the underlined portion does not give you enough information to determine the correct option. The first words of the sentence are Not only, which must be paired with but (also). (D) is the only answer that contains this construction, so it is the only possible answer.

5/1/25

Before I started working on real-world robots, I wrote about their fictional and historical ancestors. That wasn’t too different from what I do now. In factories, labs, and of course science fiction, robots continue to fuel our imaginations about artificial humans and smart machines.

Which of the following would NOT be an acceptable alternative to the underlined word?

A. nourish
B. fire
C. supply
D. stimulate

Nourish, fire, and stimulate are all idiomatic ways to indicate that something activates or encourages (i.e., fuels) people’s imaginations. Only supply cannot have this connotation. In addition, this word does not fit grammatically: x can supply y with something, but something cannot supply x about y. Because the question asks which word is NOT an acceptable alternative to fuel, (C) is correct.

4/30/25

A beetle’s wings are rarely visible. Hidden behind armored shields on the creature’s back and unfolding in whirring sheets, whisking their clumsy owners away from danger.

A. NO CHANGE
B. back, they unfold
C. back to unfold
D. back and unfold

The original version of the underlined portion creates a fragment because the statement does not contain a main (independent) clause: neither Hidden behind shields on the creature’s back, nor unfolding in whirring sheets, whisking their clumsy owners away from danger can stand on its own as a sentence. That eliminates (A). (C) and (D) are incorrect for a similar reason: each of these answers creates a dependent clause that by definition cannot stand on its own as a sentence. (B) is correct because the words they unfold act as a subject and verb that create an independent clause (they unfold in whirring sheets) and turn the statement into a complete sentence.

4/29/25

In the first half of the twentieth century, tornadoes were said so unpredictable that in order to prevent mass hysteria, the word “tornado” was forbidden from weather forecasts. Progress on the forecasting front moved slowly until the 1970s, when the first Doppler radar allowed scientists to track a storm’s development and spot the signs of a developing twister.

A. NO CHANGE
B. considered
C. viewed
D. described

(A) is incorrect because something is said to be x, but to be does not appear. (C) and (D) are incorrect for a similar reason: described and viewed must be followed by as, but this word is also missing. Only (B) is an acceptable option: although considered can be followed by to be, those words are not required. It is correct to say that something is considered x.

4/28/25

The correlation between bad moods and negative judgments allows people to make informed guesses about how others are feeling by observing their actions and choices.

A. NO CHANGE
B. judgments allow
C. judgments have allowed
D. judgments, which allow

Don’t get fooled by the plural noun judgments, which appears immediately before the verb (allows). In reality, that noun belongs to the prepositional phrase between bad moods and negative judgments, which is placed between the subject (The correlation) and the verb. Correlation is singular, and so a singular (-s) verb is required. That eliminates (B) and (C). (D) can be eliminated as well because this answer creates a fragment: although the plural verb allow agrees with judgments, it also “belongs” to which rather than to the subject of the sentence, The correlation. As a result, the sentence is missing a main verb. (A) correctly supplies a singular main verb (allows) that corresponds to the subject of the sentence.

4/27/25

The original Shinkansen, or bullet train, connects the largest Japanese cities of Tokyo and Osaka, is the world’s busiest high-speed rail line. Carrying 151 million passengers per year, it has transported more travelers than any other high-speed line in the world.

A. NO CHANGE
B. train connects
C. train connects:
D. train, which connects

To answer this question, you must consider the sentence as a whole; the underlined section alone does not give you enough information to determine the correct option. When considered independently, the underlined portion makes sense; however, the construction Osaka, is later in the sentence signals the end of a non-essential clause. In fact, the sentence contains two non-essential clauses placed back to back: or bullet train and (which) connects the largest cities of Tokyo and Osaka. To simplify the sentence and reveal the error, cross out the first non-essential clause: The original Shinkansen…connects the largest Japanese cities of Tokyo and Osaka, is the world’s busiest high-speed rail line. Clearly, that does not work grammatically. Because the end of the sentence cannot be changed, the beginning must be altered to include the start of a non-essential clause. This type of clause cannot begin with a verb; instead, it must begin with a relative pronoun (which). Now, when the first non-essential clause is crossed out, the sentence makes grammatical sense: The original Shinkansen…which connects the largest Japanese cities of Tokyo and Osaka, is the world’s busiest high-speed rail line. That makes (D) correct.

4/26/25

In the mid-nineteenth century, the Oregon Trail was the principle pathway for immigrants seeking land and opportunity on the American frontier. From its main departure points in Missouri, the grueling overland route stretched 2,000 miles over the Great Plains and the Continental Divide, finally ending in the fertile Willamette Valley or the gold fields of California.

A. NO CHANGE
B. principal pathway for
C. principle pathway to
D. principal pathway to

Based on the context, the underlined portion must be referring to the main pathway, i.e., the principal pathway. A principle is a fundamental rule or doctrine. That eliminates (A) and (C). Logically, the Oregon Trail must have been a pathway for immigrants rather than to (toward) them. That eliminates (D) and makes (B) the answer.

4/25/25

A snowflake begins to form when an extremely cold water droplet freezes onto a pollen or dust particle in the sky, this creates an ice crystal. As the ice crystal falls to the ground, water vapor freezes onto the primary crystal, building new crystals—the six arms of the snowflake.

A. NO CHANGE
B. sky and create
C. sky, creating
D. sky; creating

(A) creates a comma splice: two complete sentences separated by only a comma (tip-off: comma + this). When plugged in, (B) creates a coherent sentence but a subject-verb disagreement: the subject of the verb is an extremely cold water droplet, singular, whereas create is plural. Creates (parallel to freezes) must be used instead. (D) is incorrect because a semicolon can only be placed between two complete sentences, and creating an ice crystal is not a sentence. (Note that as a general rule, an –ing word should not follow a semicolon.) An –ing word (creating) can, however, be placed after a comma to join an independent and a dependent clause. That makes (C) correct.

4/24/25

Not so long ago, astronomers didn’t know if there were planets outside our solar system or, if there were, whether it could ever be found. But starting with the 1995 discovery of a planet circling the sun-like star 51 Pegasi, there has been a revolution.

A. NO CHANGE
B. this
C. they
D. DELETE the underlined word.

The only noun in the sentence to which the underlined pronoun could refer is planets, plural, so the correct answer must be plural as well. It and this are both singular, so (A) and (B) can be eliminated. (D) does not fit either because the sentence no longer makes grammatical sense when the underlined word is eliminated — a pronoun is needed to refer back to planets. They is plural and agrees with planets, making (C) correct.

4/23/25

In recent years, robotics has found its way into our everyday lives, changing them in fundamental ways. Designers have a central role to play in this process, which they shape the interfaces between humans and machines.

A. NO CHANGE
B. process:
C. process,
D. process that

(A) is incorrect because the word which is unnecessary and creates a nonsense construction. Because which is placed immediately after process, it appears to refer back to process; however, the information that follows (they shape the interfaces between humans and machines) refers to designers. (D) creates the exact same error; it merely replaces which with that. (C) is incorrect because it places a comma before they, creating a comma splice: two complete sentences separated by only a comma. (B) correctly uses a colon to separate two complete sentences and signal that the second sentence explains the first — that is, the second sentence describes the central role in robotics played by designers.

4/22/25

Researchers at the University of Maryland have developed a super-lightweight insulating material that, they claim, could prove to be a superior alternative to styrofoam. The material, made from tiny wood fibers, is called nanowood.

A. NO CHANGE
B. material, that they
C. material that they
D. material and they

Although in most circumstances, no comma should be placed either before or after that, this question is the exception. The key to understanding the logic of the sentence is to recognize that the words they claim, which appear after that, can function as a non-essential clause and must therefore be surrounded by commas. When the clause is removed, the sentence still makes sense: Researchers at the University of Maryland have developed a super-lightweight insulating material that could prove to be a superior alternative to styrofoam. That makes (A) the answer.

(B) is incorrect because it does not make sense to place the comma before that. If the phrase that they claim is removed from the sentence, the result is nonsense: Researchers at the University of Maryland have developed a super-lightweight insulating material could prove to be a superior alternative to styrofoam. (C) is incorrect because if the comma is removed from the underlined portion, the comma after claim no longer marks the end of a non-essential clause and is thus unnecessary.

(D) is incorrect because that rather than and must be used to refer back to insulating materials. Otherwise, the sentence does not make sense: Researchers at the University of Maryland have developed a super-lightweight insulating material and could prove to be a superior alternative to styrofoam. This construction literally indicates that the researchers could be a superior alternative to styrofoam, a meaning that is clearly ridiculous.

4/21/25

Hummingbirds have long intrigued scientists. Their wings can beat 80 times a second, and their hearts can beat more than 1,000 times a minute. They consume nothing but nectar—a sugar- and nutrient-rich liquid produced by plants—they are capable of packing on 40 percent of their body weight in fat for migration.

A. NO CHANGE
B. Because they
C. Although they
D. Since they

Be careful not to focus only on the beginning of the sentence; the information you need to answer the question is elsewhere. Start by eliminating the non-essential information between the dashes to simplify the sentence: They consume nothing but nectar they are capable of packing on 40 percent of their body weight in fat for migration. What remains is clearly a run-on. The first clause must be altered so that it becomes dependent, which means that a transition is required at the beginning of the sentence.

Next, consider what the two statements are saying: 1) Hummingbirds consume only nectar; 2) they can gain up to 40% of their body weight. Because and since are synonyms, so by default, neither (B) nor (D) can be correct. That leaves (C): although correctly conveys the contrast between the single type of food consumed by hummingbirds and the enormous amount of weight they are able to gain.

4/20/25

The Megalodon, a prehistoric ancestor of the modern shark, had a bite force of 12 to 20 tons, somewhere between six and ten times stronger than a modern Great White.

A. NO CHANGE
B. then a modern Great White.
C. than that of a modern Great White.
D. than those of a modern Great White.

(A) incorrectly compares the Megalodon’s bite force (thing) to a modern Great White (animal). Because the first side of the comparison cannot be changed, the second side must be changed so that the bite force of the Megalodon is compared to the bite force of the Great White. (B) contains the same error as (A) and also wrongly uses then instead of than to form the comparison. (D) is incorrect as well because it replaces the singular bite force with the plural pronoun those. (C) correctly uses the singular pronoun that to replace the singular noun bite force. (That of = the bite force of.)

4/19/25

Steve Desch, an astrophysicist at the University of Arizona, can see the future of exoplanet research, and it’s not pretty. Imagine, he says, that astronomers use NASA’s upcoming James Webb Space Telescope to scour the atmosphere of an Earth-mass world for signs of life. They might chase hints of atmospheric oxygen for years before realizing they were false positives produced by geological activity instead of living things.

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

A. cleanse
B. consume
C. search
D. burnish

Consider the context: the passage is talking about astronomers who are using a telescope to look carefully for, i.e., search, the atmosphere of a planet for indications of life. Even if you don’t know what scour means, that information is most directly consistent with (B). Cleanse, the literal meaning of scour, consume (eat or use up) and burnish (polish) all do not make sense.

4/18/25

With the car windows down on the first warm day of spring, the urge is unshakable. You extend your arm into the wind, tracing the city skyline in a natural motion somewhere between swimming and waving. As you move your hand, altering the flow of the air. The redirected air in turn exerts a force on your hand.

A. NO CHANGE
B. hand and alter
C. hand, you alter
D. hand to alter

The original version of the underlined portion creates a fragment because the statement does not contain a main (independent) clause: neither As you move your hand, nor altering the flow of air can stand on its own as a sentence. That eliminates (A). (B) and (D) are incorrect for a similar reason: both of these answers create a single clause that begins with as (a subordinating conjunction) and thus cannot stand on their own as sentences. (C) is correct because the words you alter act as a subject and verb that turn the second clause — the information after the comma — into a complete sentence (you alter the flow of air).

4/17/25

Although the concept of sleep-learning, also referred to as hypnopaedia, has been discredited, neuroscientists are now discovering ways to use stimuli such as sound cues during sleep to strengthen peoples’ memories.

A. NO CHANGE
B. peoples memories’.
C. people’s memories.
D. people’s memory’s.

When a question tests two consecutive nouns with apostrophes, the standard pattern is that the first noun is possessive (apostrophe) and the second is plural (no apostrophe). That is the case here: the underlined portion refers to memories belonging to people, so the first noun is possessive. (B) can be eliminated because peoples is plural rather than possessive, so the question becomes whether the apostrophe should be placed before or after -s. For regular nouns, the plural possessive is formed by adding –s + apostrophe, but people, the plural of person, is irregular. When a plural noun is irregular, the plural possessive is formed by adding apostrophe + -s, so (A) can be eliminated. (D) is incorrect as well because memory’s is the singular possessive form. (C) correctly forms the possessive of the first noun by adding apostrophe + -s and the plural of the second by adding -ies. People’s memories = memories of people.

4/16/25

Once upon a time, it seems that Mars had oceans. However, the exact appearance of these bodies of surface water is a matter of intense debate. Most evidence points towards the deep past, some 4 billion years ago, as the age where Mars could have held marine environments. Since then, the red planet has most likely been cold and arid, with only the occasional shift of climate conditions.

A. NO CHANGE
B. in which
C. which
D. in that

Where can only be used to refer to places, not times/time period, so (A) can be eliminated. (C) is incorrect because which alone should not be used to refer to a time period either. (D) is incorrect because in that is a synonym for because, a meaning that does not make sense in this context. The only two options are when and in which. Because when does not appear as a choice, in which must be used. That makes (B) correct.

4/15/25

Baseball has a long and rich history in Japanese-American diplomacy. After the sport was introduced to Japan in the 1870s by the American educator Horace Wilson, it became an important part of Japanese popular culture. Over time, baseball has served as a unifier, bringing together the people of two nations with very different histories and cultures.

A. NO CHANGE
B. educator, Horace Wilson
C. educator, Horace Wilson,
D. educator Horace Wilson

When a name appears in the middle of a sentence, as is the case here, it is always incorrect to place a comma only before the name. As a result, (B) can be eliminated automatically. Placing a comma both before and after a name indicates that the name is being used non-essentially and can be crossed out of the sentence without disturbing its basic structure or meaning. To check (C), cross out Horace Wilson and read the sentence without those words: After the sport was introduced to Japan in the 1870s by the American educator… it became an important part of Japanese popular culture. No, it does not make sense to refer to the American educator without providing his name. Although the sentence is acceptable grammatically, it does not work from a meaning standpoint. Now, the question is whether a comma is needed after the name. In this case, the answer is yes: the sentence begins with a dependent clause (After the sport was introduced to Japan in the 1870s by the American educator Horace Wilson) that is then followed by an independent clause (it became an important part of Japanese popular culture). When an independent clause follows a dependent clause this way, a comma must be used to separate them. That makes the answer (A).

4/14/25

One of the most renowned architects of the twentieth century, Frank Lloyd Wright was the pioneer of the Prairie School movement and he developed the Usonian home, his unique vision for urban planning in the United States.

A. NO CHANGE
B. and developing
C. the developer of
D. had developed

The sentence indicates that Wright was two things: the pioneer of the Prairie School movement of architecture and __________. To keep the sentence parallel, the two sides must match. The non-underlined portion of the sentence contains a noun (pioneer), so the underlined portion of the sentence must contain a noun as well (developer). (C) is the only answer to include this construction, so it is correct. Note that although it is technically grammatically acceptable, if not parallel, (A) does not work because the information that follows and is a complete sentence, and so a comma is required before that word.

4/13/25

In terms of intelligence, the octopus stands far above most other animals. During one really cool study, researchers tested whether this creature is able to distinguish between different people. Two individuals interacted with an octopus, with one acting extremely friendly and another seeming cold and standoffish. Later, when the two people entered the octopus’s living area, the octopus ignored the impersonal one in favor of the friendlier guest.

A. NO CHANGE
B. awesome
C. intriguing
D. totally neat

This question is testing register, or formal vs. informal language. Really cool, awesome, and totally neat are all overly casual when compared to the rest of the passage. Only intriguing is consistent with its moderately serious tone. That makes (C) the answer.

4/12/25

In the early days of mariachi music, players dressed informally. With increased employment opportunities and more formal presentations, however, uniforms became common. When mariachis first acquired the purchasing power to dress their groups in uniforms, the apparel they had chose most often was the charro suit, which consisted of fitted trousers, a short jacket, and an embroidered belt.

A. NO CHANGE
B. have chosen
C. chose
D. choose

All of the non-underlined verbs in the passage are in the simple past tense (became, acquired, was, consisted), so the underlined verb must be in this tense as well. (A) is not only in the past perfect (had + past participle), but it also incorrectly forms this tense: the simple past chose rather than the past participle chosen appears after had. In (B), the present perfect (has/have + past participle) is correctly constructed, but this tense is not consistent with the rest of the verbs in the passage. (D) is incorrect because choose is the present tense, which again does not fit. (C) correctly provides the simple past form, chose.

4/11/25

You can probably recall a situation, in sports or otherwise, in which you felt like you had momentum on your side: your body was in sync, your mind was focused, and you had a high level of confidence. In these moments of flow, success feels inevitable, and effortless.

A. NO CHANGE
B. you had a high confidence level.
C. your high confidence level.
D. your level of confidence was high.

The underlined portion is the third item in a list, and so it must be presented in the same format as the first two items. Both of those items begin with your, so the third item must begin this way as well. That eliminates (A) and (B). (C) is incorrect as well because each of the two previous items contains the pattern your noun + verb, and this answer does not contain a verb. (D) correctly begins the third item with your and includes a verb (was), maintaining the pattern used in the first two items.

4/10/25

Despite decades of research, the sun remains an enigma. Every 11 years or so its activity spikes, creating flares and coronal mass ejections—the plasma-spewing eruptions that shower Earth with charged particles and beautiful auroral displays. Then, however, the so-called solar maximum fades toward solar minimum, and the sun’s surface grows eerie quiet.

A. NO CHANGE
B. eerily quiet.
C. eerie quietly.
D. eerily quietly.

Logically, the suns’s surface must grow (i.e., become) quiet, not quietly, so the second underlined word must be an adjective. That eliminates (C) and (D). The adjective must in turn be modified by an adverb. (How quiet does the sun’s surface become? Eerily quiet). Note that because the adjective eerie already ends in an –ee sound, –ily must be added to form the adverb. (B) is thus correct.

4/9/25

According to research, people are generally biased toward believing that information is true. (After all, most things that we read or hear are true.) In fact, there’s some evidence that we initially process all statements as true and that cognitive effort is required to mentally mark some of them as false.

In the last sentence, the word “mark” most nearly means

A. distort
B. label
C. transmit
D. inscribe

The structure of the sentence provides a subtle but important clue to the meaning of the underlined word. The construction we initially process all statements as true and that cognitive effort is required to mentally mark some of them as false indicates that the word in question must be generally consistent with the idea of processing or perceiving. The only option that makes sense in that context is label: the sentence is saying that the brain requires extra information to assign things to the “false” category, i.e., to label them as such. Transmit (send) and inscribe (engrave) do not fit at all, but be careful with distort: something that is false does indeed provide a distorted picture, but the underlined word itself does not actually have this meaning.

4/8/25

It has taken a while for scientists to piece together the riddle of just when and where cats first became domesticated. In many cases, this type of question can be easily answered by the archaeological record, but in this instance the matter is complicated by the fact that wild cats and domesticated cats have remarkably similar skeletons.

All of the following placements for the underlined word would be acceptable EXCEPT

A. where it is now.
B. after the word can.
C. after the word answered.
D. after the word the.

Easily is an adverb and can only modify a verb. Because modifiers must be placed next to the words they modify, the three acceptable answers must place easily next to verbs. In (A), be is a verb; in (B), can is a verb; and in (C), answered is a verb. Only (D) does not place easily either before or after a verb (the, archaeological). Because the question asks you to identify which placement would NOT be acceptable, (D) is correct.

4/7/25

Knowing that an employee demonstrates high levels of conscientiousness won’t tell you whether his or her work will be careful or sloppy if you inspect it at a particular moment. But if a large company hires hundreds of employees which are all conscientious, this strategy will likely pay off with a small but consistent average increase in careful work.

A. NO CHANGE
B. who
C. whom
D. DELETE the underlined word.

The underlined pronoun refers to employees, i.e., people. Which should be used to refer to things only, so (A) can be eliminated. (C) is incorrect because whom would be placed right before the verb are, and as a rule, whom should not come before a verb. (D) is incorrect because deleting the underlined word would create a nonsense construction (But if a large company hires hundreds of employees are all conscientious…) — a pronoun is needed to refer back to employees. (B) correctly uses who to refer to people. Unlike whom, this pronoun can be placed before a verb.

4/6/25

Growing hardy and plentiful on short, stout bushes, the prairie cherry’s ornamental blooms and glossy leaves produce a deep-red fruit that is less sweet than the traditional cherry, and can be eaten straight from the tree.

A. NO CHANGE
B. cherry, and can be eaten straight,
C. cherry and can be eaten straight
D. cherry and can be eaten straight,

Comma + and = period, but a period cannot be plugged in without creating nonsense: Growing hardy and plentiful on short, stout bushes, the prairie cherry’s ornamental blooms and glossy leaves produce a deep-red fruit that is less sweet than the traditional cherry. Can be eaten straight from the tree. As a result, the comma is unnecessary, and (A) and (B) can be eliminated. (D) is incorrect as well because the comma after straight incorrectly places a comma before a preposition (from). (C) is correct because no punctuation is needed in the underlined section.

4/5/25

During the early days of space travel, astronauts squeezed most of their meals out of tubes. A sugary, orange-flavored drink, sold commercially as Tang, was considered a tasty treat. Food was fuel, and little more. Meals are stored in locker trays held by a net so they won’t float away. In fact astronauts can dine on a variety of freeze-dried meals using regular forks and spoons. And, for a few years, crews in the International Space Station (ISS) have been able to savor a taste of food that’s actually fresh.

Which of the following provides the best transition between the previous sentence and the sentence that follows?

A. NO CHANGE.
B. Salt and pepper are available, but only in liquid form.
C. Today, eating in space has become much less of a chore.
D. Being in space can put a damper on an astronaut’s appetite.

Although the question asks about the underlined portion in terms of the previous and following sentences, you may find it helpful to take more information into account. The beginning of the passage focuses on the fact that eating in space had little resemblance to that act on Earth and involved unappealing food. The latter part of the passage emphasizes that more recently, astronauts’ food has been considerably improved. The underlined portion must therefore set up the contrast between those two ideas and introduce the fact that eating in space is more pleasant than it used to be. In other words, it “has become much less of a chore.” That makes the answer (C). All the other options are off-topic.

4/4/25

Fraudulent images have been around for as long as photography itself, but Photoshop ushered image doctoring into the digital age. Now, artificial intelligence is poised to take photographic fakery to a new level of sophistication thanks to artificial neural networks who’s algorithms can analyze millions of pictures of real people and places and use them to create convincing fictional ones.

A. NO CHANGE
B. who’s algorithms’
C. whose algorithm’s
D. whose algorithms

Who’s = who is, and you would not say …thanks to artificial neural networks who is algorithms can analyze millions of pictures. Rather, the possessive whose must be used. Whose algorithms = the algorithms of artificial neural networks. That eliminates (A) and (B). (C) is incorrect because algorithm’s is possessive, and a possessive noun can only be placed before another noun. The word following algorithms is can, which is a verb, and so no apostrophe should be used. The plural algorithms is thus correct, making (D) the answer.

4/3/25

The human eye may seem capable of taking in a lot of information, but in reality it can focus on only a thumbnail-sized area of vision—the brain fills in the rest. Furthermore, peripheral vision provides less details than central vision does, conveying images at a much lower resolution.

A. NO CHANGE
B. less details then
C. fewer details than
D. fewer details as

Less can only be used to modify singular, non-countable nouns. It would be acceptable to say less detail because detail is singular and cannot be counted, but details is plural and can be counted. Fewer must be used to modify plural nouns, making (C) and (D) the only possible options. In addition, the comparative (-er) form of an adjective must be paired with than, not as, eliminating (D) and making (C) correct.

4/2/25

When trying to learn new material, you might assume that the more work you put in, the better you will perform. Yet taking the occasional down time – to do literally nothing – may be exactly what you need. Dimming the lights, sitting back, and enjoying a few moments of quality contemplation will help one retain the information much more effectively.

A. NO CHANGE
B. us
C. you
D. them

To answer this question, it is necessary to consider the underlined pronoun in the context of the passage as a whole; the sentence in which that word appears does not provide enough information to answer the question. If you look back at the first two sentences, you can notice that they are addressed to you (you might assume, the more work you put in, may be exactly what you need). To keep the passage consistent, you must be used in the last sentence as well, making the answer (C).

4/1/25

Kagome baskets are characterized by a symmetrical pattern of interlaced triangles. A pattern that has preoccupied physicists for decades.

A. NO CHANGE
B. triangles, it is a pattern
C. triangles—a pattern
D. triangles; a pattern

The statement A pattern that has preoccupied physicists for decades is not a complete sentence because it is missing a main verb that corresponds to the subject. The verb has preoccupied “belongs” to the word that rather than to the subject, A pattern. Because it is not a sentence, it cannot follow a period or semicolon, eliminating both (A) and (D). (B) is incorrect because it contains a comma splice — two complete sentences separated by a comma (tip-off: comma + it). (C) correctly uses a single dash to create a single sentence broken into two parts and create a brief dramatic pause between those parts. Note that while a dash used this way must be preceded by a complete sentence, it can be followed by a fragment.

Explanation