Designing and building a hotel suite is no easy endeavor. Now imagine designing and creating one out of ice. Since 1990, the Icehotel in Jukkasjärvi, Sweden, rebuilds itself north of the Arctic Circle each winter, creating a tourist destination made entirely out of ice and snow.


B. has rebuilt
C. had rebuilt
D. rebuilt


The tip-off word for this question is since — it indicates that the sentence is describing an action that begins in the past and that is continuing into the present (the ice hotel began rebuilding itself each winter in 1990 and is still doing so today). The tense that corresponds to this type of action is the present perfect (has/have + past participle), making the answer (B).





Even when you are asleep, your brain cells continuously buzz with a low level of electrical activity akin to white noise on the radio. Occasionally, this electrical clamor reaches a threshold that triggers the firing of neurons. New research suggests that when random firing occurs in the wake-promoting neurons, a person briefly jerks awake. But that is countered by a suite of sleep-promoting neurons that helps him or her fall quickly back to sleep.


B. one
C. you
D. us


To identify the correct pronoun, you must look back to the previous sentence to identify the antecedent. Logically, it can only be the singular noun a person.  The only option that corresponds to that antecedent is the phrase him or her, so (A) is correct.





Driverless cars “perceive” the world around them using lasers, radar, GPS and other sensors, but their perceptions can be very different from those of human eyes. At the same time, their active response times can be extremely fast—or sometimes even excessive slowly—when compared to the speed of human intervention.


B. excessively slow
C. excessively slowly
D. excessive slowly


As a general rule, when adverb/adjective pairs are tested, the first word will be an adverb (-ly) that modifies the adjective that follows (no -ly). That is the case here: the second word serves to modify the noun phrase active response times, and so it must be an adjective; an adverb is then required to modify the adjective. (How slow were the response times? Excessively slow). Alternately, you can recognize that the underlined phrase must be parallel to extremely fast, which contains the adverb-adjective pattern. Either way, (B) is correct.





You probably don’t remember, but you woke up at least 100 times last night. These spontaneous disruptions, each lasts less than 15 seconds, occur roughly every five minutes and don’t seem to affect how well-rested you feel. They are unrelated to waking up from a bad dream. Instead, they seem to be linked to some internal biological mechanism.


B. each of them lasts
C. each one lasts
D. each lasting


The commas surrounding each lasts less than 15 seconds indicates a non-essential clause that can be eliminated from the sentence without affecting its basic structure: These spontaneous disruptions…occur roughly every five minutes and don’t seem to affect how well-rested you feel. As a rule, a non-essential phrase or clause must be dependent — that is, it cannot stand on its own as a grammatically complete sentence. (A), (B), and (C) are all complete sentences that contain subjects and verbs. Only (D), with the gerund lasting, is dependent and can be used non-essentially.





To travel westward across the United States is to experience a striking landscape metamorphosis. Stately hardwood trees give way to squat shrubs, verdant cornfields to brown wheat, and lush grasslands with cacti and creosote bush. The air dries out, and the land is often parched.


B. grasslands have
C. grasslands for
D. grasslands to


The underlined section is part of the third item in a list. The previous two items follow the patterns x gives way to y, even though the words give way are only implied after the first item: Stately hardwood trees give way to squat shrubs, verdant cornfields (give way) to brown wheat. The third item must continue this pattern by using the preposition to, making (D) correct.





Light enables us to see, but it affects many other body systems as well. In the morning, light advances our internal clock, while light at night delays the clock, making us more inclined to remain awake. Light also suppresses a hormone called melatonin, which signals to the rest of the body that it’s night-time, including the parts regulating sleep.


B .to the rest of the body that it’s night-time, which includes the parts regulating sleep.
C. that it’s night-time to the rest of the body, this includes the parts that regulate sleep.
D. that it’s night-time to the rest of the body, including the parts that regulate sleep.


As a rule, modifies should be placed as close as possible to the word or phrase they modify. In this case, including the parts that regulate sleep must modify the body. As a result, these two elements must be placed next to one another. (A) can be eliminated because including the parts that regulate sleep is placed next to night-time, creating a misplaced modifier. (B) creates the same error: the phrase which includes the parts regulating sleep must refer back to the noun that precedes it — again night-time. (C) corrects this error but introduces a comma splice: two complete sentences separated by only a comma (tip-off: comma + this). (D) corrects the original error by placing including the parts that regulate sleep next to the body without introducing any new problems.





Every night, trillions of sea creatures—whales, jellyfish, swarms of shrimp, and plankton, take part in what some call the largest mass migration on the planet. From depths of at least 2,000 feet, they swim to the ocean’s surface, in a wave of animals that propagates as the sun sets around the planet. By daylight, they return below.


B. whales; jellyfish, and swarms of shrimp and plankton,
C. whales, jellyfish, swarms of shrimp, and plankton—
D. whales, jellyfish, swarms of shrimp, and plankton


The phrase whales, jellyfish, swarms of shrimp, and plankton is non-essential because the sentence still makes sense when it is removed: Every night, trillions of sea creatures…take part in what some call the largest mass migration on the planet. As a result, a second dash must be used to mark the end of the non-essential clause. That makes (C) the only possible answer. In the other answers, the various types of punctuation within the list are only a distraction.





The world in which Picasso lived was particularly supportive of his developing celebrity. His family cultivated his creative passion, he had clusters of peers who inspired him, and he had the good fortune to be born at a time when new ideas in science, literature, and music energized his work. However, the advent of mass media allowed him to achieve widespread fame.


B. In contrast,
C. In fact,
D. Moreover,


To answer this question, ignore the transition already in the passage an consider the information before and after the last sentence. The information before indicates that Picasso was born in an era conducive to his success, and the final sentence continues that idea by explaining how he was able to become so famous. However and in contrast, both indicate a contradiction, so (A) and (B) can be eliminated. In fact does not quite work either. This transition serves to emphasize a previous statement on the same subject, but the previous sentence focuses on innovations in various fields, whereas the last sentence focuses on the media. As a result, (C) can be eliminated. (D) is correct because moreover serves to introduce an idea that is new but related to the previous one.





Although quite different from one another, humans, plants and some fungi share gravitropism, the ability to know up from down. This trait helps us survive by sensing Earth’s gravitational pull, humans can move around without getting dizzy, and plants and fungi can obtain nutrients and reproduce.


B. survive; by sensing Earth’s gravitational pull—
C. survive: by sensing Earth’s gravitational pull,
D. survive, by sensing Earth’s gravitational pull,


(A) and (D) are both incorrect because they create commas splices: two complete sentences separated by a comma. (D) also incorrectly places a comma before a preposition (by). (B) can be eliminated as well because the dash after pull creates an unnatural break in the sentence: the explanation (how gravitropism helps us survive) does not begin right afterward, nor is it a logical place for a dramatic pause. In contrast, (C) is correct because it places a colon at the beginning of the explanation and logically separates the two sentences.





Spider webs come in many forms, from the trampoline-like construction of the sheet web spider to the instantly recognizable filigree of the orb weaver. Orb-style webs are made by diverse spiders, however, and there are two different types: one that’s sticky and one that’s not.


Which of the following is the LEAST acceptable alternative to the underlined portion?


A. one sticky and one not.
B. one is sticky, and the other is not.
C. one sticky, the other one that’s not.
D. one of them is sticky, and the other is not.


(A), (B), and (D) all contain parallel constructions (one…one; one is…the other is; and one of them is…the other is), whereas (C) contains a non-parallels structure: one + adjective..the other one + that’s. That lack of parallel structure makes it the most awkward, LEAST acceptable option. As a result, (C) is correct.





For millennia, humans lived in synchrony with the natural cycle of light and dark. This doesn’t mean that everyone went to sleep as soon as the sun set. Studies of pre-industrial societies, such as tribes living in Tanzania or Bolivia today, suggest that people stay up for several hours after dark, often socializing by firelight. In fact, the amount of sleep they get is quite like people in industrialized countries, but the timing is more in line with the natural cycle of day and night: they tend to go to bed earlier and get up just before dawn.


The passage implies that people in industrialized countries


A. sleep for shorter periods than people in pre-industrial societies.
B. have sleep patterns that are less in sync with the natural light cycle.
C. tend to go to bed shortly after dark.
D. socialize after dark as a way of avoiding sleep.


The passage states that in comparison to people in industrialized countries, people in pre-industrial countries have sleep patterns more in line with the natural cycle of day and night. As a result, it can be inferred that people in industrialized countries have sleep cycles that are  less in line with the natural cycle of day and night, i.e., “less in sync with the natural light cycle.” That makes the answer (B). (A) is incorrect because the passage states that people in pre-industrial and industrial societies get around the same amount of sleep; (C) is incorrect because the passage states that people in pre-industrial societies stay up for several hours after dark, and that they go to bed earlier than people in industrial societies. The implication is that people in industrial societies stay awake longer than a few hours after dark — not that they go to bed “shortly after dark.” (D) is entirely unsupported by the passage.





The microbial denizens of Monterey Canyon are far different from many of it’s surface-dwelling cousins, making food out of rocks and dead debris and harvest energy from methane that seeps out from the ocean floor. To survive in this dark, high-pressure, low-oxygen, low-nutrient environment, they form all kinds of cooperative relationships.


B. its
C. they’re
D. their


Don’t get distracted by the singular noun Monterey Canyon. The underlined pronoun must refer to a noun that has surface-dwelling cousins. Logically, the only noun in the sentence to which that could apply is microbial denizens (inhabitants), which is plural. As a result, the underlined pronoun must be plural as well. That eliminates (A) and (B). (C) can be eliminated as well because they’re = they are, and you would not say The microbial denizens of Monterey Canyon are far different from many of they are surface-dwelling cousins. That leaves (D), which correctly provides the plural form, their. Their surface-dwelling cousins = the surface dwelling cousins of the microbial denizens (of Monterey Canyon).





People with synesthesia are able to associate the perception of color to letters and numbers. This condition is often described as a joining of the senses – one that allows a person to see sounds or hear colors.


B. at
C. with
D. by


The correct idiom is associate x with y; any other preposition is incorrect. That makes (C) the answer.




For Deborah Willis, the photograph is an instrument of memory that can be used to explore the value of self, family, and memory in documenting everyday life. She first became aware of the photograph as an important storytelling device as young girl growing up in Philadelphia; today, she is a renowned photographer who uses her work to convey stories about family life.


B. self, family and, memory
C. self, family and memory,
D. self family and memory


In a list of three items, commas must always be placed between the first two items, so (D) can automatically be eliminated. (B) can be eliminated as well because a comma can only be placed before and, not after. Although the comma before the third item is optional, (C) can also be eliminated because when this answer is plugged into the sentence, the comma after memory results in a comma being incorrectly placed before a preposition (in). (A) correcty places commas between the items in the list, without adding any additional, unnecessary punctuation.





Like mathematicians, poets create layers of meaning by utilizing words and images that have multiple interpretations and associations. Both mathematicians and poets strive for economy and precision, they select exactly the words they need to convey their meaning.


B. precision, selecting
C. precision and selects
D. precision, but they select


(A) is incorrect because it creates a comma splice: two complete sentences separated by only a comma (tip-off: comma + they). (C) is incorrect because the gerund selecting is not parallel to strive and does not agree with the subject mathematicians and poets. (D) is grammatically correct but illogical because the two halves of the sentence do not express a contrast. On the contrary, they express two very closely connected ideas. (B) correctly uses an -ING word (participle) to eliminate the comma splice and smoothly join the two halves of the sentence.





The Earth outside your window might appear quiet, but that’s because you’re looking at a tiny slice in time and space. Expand your view, and you’ll see plates shift, earthquakes ripple, and volcanoes erupting along tectonic boundaries.


B. that erupt
C. erupt
D. erupted


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 contain the construction noun + conjugated (present-tense) verb, so the third item must contain this construction as well. This item already contains a noun (volcanoes), so only a conjugated verb in the present is required. (C) is the only answer that fits this pattern, so it is correct.





It took only ten minutes for Harvey Ball to create the smiley face. It is now an iconic image with two black marks for eyes and a black grin on a bright yellow background. After Ball presented his work to the State Mutual Life Assurance Company, which had commissioned the image to boost employee morale, he was paid just $45 for his work.


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


A. face—a now-iconic image
B. face: a now-iconic image
C. face; a now-iconic image
D. face, now an iconic image


The easiest way to answer this question is essentially to play “which of these things is not like the others”? The key is to notice that all of the answers use some form of punctuation to separate a complete sentence (It only took ten minutes for Harvey Ball to create the smiley face) from a fragment (a now-iconic image/now an iconic image). A dash, a colon, and a comma can all be followed by a fragment, whereas that is never the case for a semicolon. Because the question asks which answer would NOT be acceptable, (C) is correct.





In a recent study, researchers at Penn State solicited the school’s faculty, staff and students to complete a series of online questionnaires about their fitness, commuting habits, and comfort and ability on a bike or as pedestrians. Only a few of the 505 respondents went by foot or bike. Most of whom were students.


B. bike, most of whom
C. bike, and most of whom
D. bike, most of them


The construction pronoun + of whom, e.g., most of whom, many of whom, several of whom, is always dependent and cannot stand by itself as a complete sentence. That eliminates (A). (C) is incorrect because it is grammatically identical to (A): comma + and = period, so the same error results. (D) creates the flipside of the original error: pronoun + of them is always independent and can stand by itself as a sentence. As a result, placing this construction after a comma creates a comma splice. (B) is correct because it uses a comma to separate an independent clause (Only a few of the 505 respondents went by foot or bike) from a dependent clause (most of whom were students).





After swimming for years in a giant loop from nesting grounds in North Carolina and Florida to North Africa, sea turtles find their way back to nest on beaches within about 50 miles of where they were born. A new study suggests that the turtles are able to accomplish this feat by “memorizing” their home beach’s distinctive magnetic signature through a process known as geomagnetic imprinting.


B. there home beaches’
C. their home beaches
D. they’re home beach’s


They’re = they are, and it does not make sense to say …the turtles are able to accomplish this feat by “memorizing” they are home beaches, so (D) can be eliminated. There refers to a place, but that does not fit here since the underlined pronoun is not actually replacing beaches. The only logical interpretation of the underlined pronoun is that it refers to the home beaches of the turtles, i.e., their (possessive) beaches. That means the answer is either (A) or (C). (C) can be eliminated because beach is followed by another noun (distinctive magic signature) and must be possessive: home beach’s magnetic signature = magnetic signature of the home beach. (A) is thus correct.





In 2008, chunks of space rock crashed in the Sudanese desert. Now, scientists believe that diamonds discovered inside one of the recovered meteorites might of come from a destroyed planet that orbited our sun billions of years ago. If their hypothesis is confirmed, it would be the first time anyone has recovered fragments from one of our solar system’s so-called “lost” planets.


B. might of came
C. might have come
D. might have came


As a rule, might (along with should, could, and would) must be followed by have, not of. Questions like this one play on the similarity in sound between the two words. Since of is incorrect, (A) and (B) can both be eliminated. (D) can be eliminated as well because any form of to have must be followed by the past participle form of a verb (come) rather than the simple past (came). That makes (C) correct.





It was one of the shortest train rides I had ever taken: just 10 minutes and one stop from the Swiss city of Neuchatel. When I disembarked, everything seemed different at first, I couldn’t put my finger on what was strange. Perhaps it was something about the architecture? People’s body language? Even the air, crisp and fresh, felt somehow changed.


B. different, at first
C. different, so at first
D. different, but at first


(A) is incorrect because the comma before I creates a comma splice — two complete sentences separated by a comma. (Note that comma + pronoun is a tip-off for a comma splice.) (B) creates the same error as (A); it simply moves the placement of the comma. (C) is grammatically acceptable but creates an illogical relationship: the fact that the narrator could not put [his/her] finger on what was strange is not a result of the fact that everything seemed different. But is a much more logical transition because it accurately conveys the contrast between the two parts of the sentence. (D) is thus correct.





Although it’s well known that people should pace themselves while they study, new research suggests that it is best to aim for “minimal interference” during breaks – that is, to avoid any activity that could tamper in the delicate task of memory formation.


B. to
C. around
D. with


The verb tamper must be followed by the preposition with; any other preposition is not idiomatic. That makes the answer (D).





Some people can’t see differences in colors—so-called color blindness—because of a defect or absence of cones: cells in the retina that are sensitive to high levels of light. However, the distribution and density of these cells also varies across people with “normal” vision, causing everyone to experience the same color in a slightly different way.


B. vary
C. has varied
D. would vary


The answer choices include a mix of singular verbs (varies, has varied) and plural verbs (vary), so start by identifying the subject and determining whether it is singular or plural. In this case, the sentence contains a compound (plural) subject: two singular nouns joined by and (distribution and density). As a result, a plural verb (vary) is required. (A) and (C) are singular and can thus be eliminated. (D) is incorrect as well because there is no need to shift tenses. In addition, would vary is in the conditional, a tense that is used to refer to actions that could happen — not the case here. (B) is thus correct.





On his first and only visit to Japan, in the late fall of 1922, Albert Einstein was wowed by the beauty of the country and the refinement of the culture. The populace was equally impressed by the visitor, greeting him on his arrival in Kobe with great fanfare. Einstein was, after all, not just the era’s best-known scientist, but arguably the most famous person in the world.


B. captivated
C. tickled pink
D. knocked out


This question is testing register, or formal vs. informal language. Wowed, tickled pink, and knocked out are all far too informal and inconsistent with the passage’s moderately serious tone. Captivated is the only answer that matches.





The modern concept of bike sharing – offering bikes for short-term public rental from multiple stations in cities – originated in Copenhagen in 1995. When bikeshares began to be implemented in the United States more than a decade later, they encountered some stumbling blocks. Washington, D.C., led the way, launching SmartBike in 2008. Two years later, in response to increasing demand from suburban dwellers, it began offering an expanded network called Capital Bikeshare, which now boasts over 480 stations and a daily ridership of 5,700.


Which choice provides information that is most relevant at this point in the paragraph?


B. remained limited in scope.
C. met with resistance from drivers.
D. quickly grew in popularity.


To answer this question, you must focus on the information that comes after that underlined statement — the beginning of the passage does not provide enough information. If you read the sentences after the underlined section, you’ll see that bikeshares have done very well in the United States, as indicated by the phrase increasing demand and the fact that Capital Bikeshare now boasts over 480 stations and a daily ridership of 5,700. As a result, the correct answer must be positive and consistent with that information. (A), (B) and (C) are all negative, but the phrase quickly grew in popularity in (D) is consistent with the idea of an expanded network. That makes (D) correct.





The Bajau people are able to dive dozens of feet underwater without conventional diving aids such as wetsuits and oxygen tanks. Instead, they rely on weights, handmade wooden goggles, and taking a single breath of air.


B. they take
C. take
D. DELETE the underlined word.


The underlined word is part of the third item in a three-item list. The first two items consist of nouns (weights, handmade wooden goggles), so the third item must also consist of a noun (a single breath of air). As a result, no verb should be placed at the beginning of the third item, making (D) correct.




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