Test: SC Mixed - GMAT MCQ

The original sentence begins with a modifier ("though considered aesthetically primitive at the time") that logically addresses Rousseau's art. But the grammatical subject of the modifier is Rousseau himself. This is incorrect. Moreover, the use of "like" in the phrase "painted like he was naive" is incorrect. "Like" is not synonymous
with "as if". For example, "She dances like she's never heard music before" is incorrect, but "She dances as if she's never heard music before" is correct.
(A) This choice is incorrect as it repeats the original sentence.
(B) CORRECT. Henri Rousseau's canvasses are correctly placed as the subject of the opening modifier. Additionally, "naive" functions as an adjective describing "style" thereby replacing the incorrect phrase "like he were naive."
(C) This choice incorrectly places Henri Rousseau (instead of his paintings) as the subject of the opening modifier "though considered aesthetically primitive . . ." Additionally, the phrase "style that has become an icon of Post-Impressionism" is incorrect. Rousseau, not his style, later became an icon.
(D) The phrase "style that was later iconic of Post- Impressionism" is both awkward ("iconic of") and incorrect. Rousseau, not his style, later became an icon.
(E) The subject "the canvases of Henri Rousseau are icons of Post-Impressionism" is incorrect. Rousseau, not his style, later became an icon. Moreover, this choice incorrectly uses "due to" where "because of" would be needed. Due to" functions as an adjectival phrase and is used to modify a noun (e.g., His failure was due to his laziness.). "Because of" functions as an adverbial phrase and is used to modify a verb or verb phrase (e.g., He failed because of his laziness.).

The original sentence contains several errors. First, "differences in" is not properly used to compare two explicit things. For example, "The difference in color is more important than the difference in size" is correct, but "The difference in the color of the apple and the color of the pear..." is not correct. Instead, it should be "The difference
between the color of the apple and the color of the pear..." Second, after the construction "it is essential that", one must use the subjunctive mood. In this case, "ascends" (which is indicative, not subjunctive) should be "ascend". Third, the plural pronoun "they" is used to refer to "a diver", which is singular.
(A) This choice is incorrect as it repeats the original sentence.
(B) This choice incorrectly uses the plural pronoun "they" to refer to the singular noun "a diver."
(C) This choice incorrectly uses "differences in" where "difference between" is required. Additionally, it uses the
indicative mood "ascends" where the subjunctive mood ("ascend") is required. Finally, the construction "the human body's internal pressure and that of the ocean" is not parallel.
(D) This choice incorrectly uses "differences in" where "difference between" is required. Additionally, the plural pronoun "they" incorrectly refers to the singular noun "a diver." Finally, the construction "the human body's internal pressure and that of the ocean" is not parallel.
(E) CORRECT. The phrase "difference between" correctly replaces "differences in." Additionally, the verb "ascend" is in the subjunctive mood. Finally, the singular pronoun "he" correctly refers to the singular "a diver."

The original sentence contains the wordy and awkward construction "the reasons why the Civil War was triggered." Also, the correct idiom is "to regard X as Y", not "to regard X to be Y".
(A) This choice is incorrect as it repeats the original sentence.
(B) CORRECT. This choice uses the concise phrase "what triggered the Civil War" and uses the idiomatic phrase "regard slavery as the sole cause" (regard X as Y).
(C) This choice incorrectly uses the unidiomatic "slavery is not regarded . . . to be the sole cause." Also, the main clause has been rewritten in the passive voice unnecessarily.
(D) This choice contains the redundancy "reasons why" and the awkward phrasing "despite research remaining." (E) This choice incorrectly introduces an ambiguous pronoun ("it") that could refer either to slavery or to the Civil War.

The original sentence contains several errors. First, the proper idiom is "to regard as" not "to regard to be". Second, the initial modifier "regarded by analysts to be the result of tensions during the Cold War" should modify "sales" and not "the spy novel." Third, the proper idiom is "to perceive as" not "to perceive like".
(A) This choice is incorrect as it repeats the original sentence.
(B) The modifier "regarded by analysts to be the result of tensions during the Cold War" incorrectly describes the spy novel when it should modify sales of the spy novel. Moreover, the modifier use of "regarded . . . to
be" is unidiomatic.
(C) The modifier "regarded by analysts as the result of tensions during the Cold War" incorrectly describes the spy novel when it should modify sales of the spy novel. Additionally, the phrase "perceived the U.S.S.R like" is unidiomatic.
(D) The modifier "reaching the zenith of its sales in the 1960s" incorrectly describes the spy novel when it should modify sales of the spy novel.
​(E) CORRECT. "Sales" is correctly positioned as the subject of the opening modifier. Additionally, the phrases
"regarded by analysts as . . ." and "perceived the U.S.S.R as" are idiomatic.

The subject of the original sentence is "the number of acres", which is singular. The main verb, however, is "have increased", which is plural. We need to find a choice that replaces "have" with "has". Moreover, the phrase "due to" is incorrect in this context. "Due to" is a phrase that must describe a noun. "The fire was due to drought"
is correct, but "There was a fire due to drought" is not. When describing a verb phrase, "because of" is preferable: "There was a fire because of drought."
(A) This choice is incorrect as it repeats the original sentence.
(B) The plural verb "have been" does not agree with the singular subject "the number of acres." Additionally, the
passive voice "have been increased" is incorrect. Finally, the phrase "due to drought . . ." is unidiomatic since "because of" (not "due to") should be used to modify the verb phrase "have become an ongoing threat."
(C) The modifier "which has become an ongoing threat . . ." contains the singular verb "has" which does not agree with the plural subject "wildfires."
(D) The phrase "due to drought . . ." is unidiomatic since "because of" (not "due to") should be used to modify the verb phrase "have become an ongoing threat."
(E) CORRECT. The singular verb "has" agrees with the singular subject "the number of acres." Additionally, "because of drought . . ." is properly used to modify the verb phrase "have become an ongoing threat."

The original sentence contains the idiom "not only" which must be paired with "but also" (not simply "also") in order to be idiomatic. Moreover, in the expression "not only X, but also Y", X and Y must be in parallel form. The two elements "for the convenience . . ." and "it ushered . . ." are not in parallel form.
(A) This choice is incorrect as it repeats the original sentence.
(B) This choice incorrectly uses a semicolon to separate a dependent clause and an independent clause. A semicolon can only be used to separate two independent clauses (i.e., clauses that can stand alone). Further, "not only" is unidiomatic when used without "but also."
(C) CORRECT. This choice contains the proper idiom pairing "not only" with "but also." Both elements of the idiom are followed by the phrase "because it . . . " thereby creating a parallel structure.
(D) This choice contains the unidiomatic pairing of "not just" with "but also." Additionally, the two elements "for the convenience . . ." and "because it ushered . . ." are not in parallel form.
(E) This choice contains the awkward and unidiomatic phrase "not only in addition" which obscures the meaning of
the sentence.

The original sentence contains a lot of clauses in a confusing order. We need to find an answer choice that rephrases the sentence in a clear and concise manner. Also, the phrase "though now eaten in large quantities around the world and harmless" contains two elements that are not parallel. Moreover, "including belladonna" is
incorrect left dangling. It should be "which includes belladonna." Finally, "itself" could  refer either to "tomato" or to "belladonna".
(A) This choice is incorrect as it repeats the original sentence.
(B) The pronoun "it" is ambiguous as it could refer either to "the nightshade family" or "belladonna" or "tomato." Additionally, the phrase "though now eaten in large quantities around the world and harmless" contains two elements that are not parallel.
(C) The phrase "including belladonna" does not properly modify anything.
(D) CORRECT. The opening phrase contains the two parallel elements "eaten in large quantities . . ." and "known to be harmless." The phrase "which includes belladonna" correctly modifies the "nightshade family." Finally, the pronoun "it" unambiguously refers to the tomato.
​(E) The phrase "including belladonna" does not properly modify anything.

The word "being" is unnecessary in the opening modifier "being one of the most significant developments . . ." Moreover, the past perfect verb "had turned" coupled with the simple past verb "was" reverses the chronological order of the events. The tenses run counter to the logic of the sentence by incorrectly suggesting that the
invention of the cotton gin happened before the cotton cloth became expensive.
(A) This choice is incorrect as it repeats the original sentence.
(B) The words "have been" are unnecessary in the opening modifier. The fact that "have been" is in the present
perfect tense also incorrectly suggests that the invention of the cotton gin is somehow ongoing.
(C) This choice incorrectly alters the meaning of the sentence by using the phrase "despite its previous expense" in place of the phrase "despite the fact that it had previously been expensive." "Expense" and "expensive" have different meanings. The word "expense" simply means "cost" so this choice essentially states that the cotton gin was now affordable despite its previous cost. This does not convey the fact that the previous cost was high (expensive).
(D) CORRECT. The modifier "one of the most significant developments of the nineteenth century" eliminates the unnecessary word "being." The simple past verb "turned" coupled with the past perfect "had previously been" correctly expresses the fact that cotton cloth "turned into an affordable commodity" after it "had previously been expensive." The later past event uses the simple past tense, whereas the earlier past event uses the past perfect
tense.
(E) The word "being" is unnecessary in the opening modifier. Additionally, in the expression "from a previously expensive commodity to an affordable one" the word "previously" is redundant since its meaning is already contained in the expression "from X to Y."

The original sentence contains several errors. First, the subject of the original sentence is "the lead attorney and his assistant", yet the corresponding verb is "was injured". The subject and the verb do not agree in number – one is plural, the other singular. Second, "despite" is not properly used with a verb phrase. Instead, it requires a noun or noun phrase. For example, "Despite eating the apple..." is not correct, but "Despite his eating the apple..." is correct. Third, "injured seriously enough to warrant medical attention" is incorrect in this context. "X enough to Y" is
used when the emphasis is on Y. "So X as to Y" is used when the emphasis is on X. For example, "I am tall enough to touch the ceiling" implies that the focus is on the fact of being able to touch the ceiling. "So tall as to be able to touch the ceiling" implies that the focus is on the fact of being tall. Finally, the use of the pronoun "him" is ambiguous, since it could refer to either the attorney or his assistant.
(A) This choice is incorrect as it repeats the original sentence.
(B) CORRECT. It eliminates the subject-verb agreement issue and ensures that "despite" is followed by a noun ("the fact"). Additionally, the choice uses the correct expression "so X as to Y" to emphasize the seriousness of the injury. Finally, the sentence is reworked to avoid pronoun ambiguity.
(C) The pronoun "him" has an ambiguous antecedent, since it could refer either to the attorney or his assistant.
(D) The singular verb "was" does not agree with the plural subject "the lead attorney and his assistant." Additionally the phrase "injured seriously enough to warrant immediate medical attention" incorrectly emphasizes the medical attention over the seriousness of the injury,
(E) The pronoun "him" has an ambiguous antecedent, since it could refer either to the attorney or his assistant. Additionally, the word "despite" is incorrectly followed by the verb "entering" instead of a noun or noun phrase.

The original sentence incorrectly omits "that" following the verb "suggest." Moreover, it contains the incomplete construction "as . . . or worse than" (missing the second "as").
(A) This choice is incorrect as it repeats the original sentence.
(B) This choice incorrectly omits "that" following the verb "suggest" and it contains the unnecessary word "just." Moreover, it contains the incomplete construction "as . . . or even worse than" (missing the second "as").
(C) CORRECT. This choice correctly uses the word "that" to introduce a clause that follows the verb "suggest." Also, it contains the complete construction "as . . . as or worse than."
(D) This choice incorrectly omits "that" following the verb "suggest."
(E) This choice contains the incomplete construction "as . . . if not worse than" (missing the second "as").

The original sentence uses the relative pronoun "that" where "who" is preferred because the antecedent is a group of people. Also, the prepositional phrase "by a gentile Dutch couple" is placed in such a way as to suggest that the occupation was carried out by the couple. Finally, the pronoun "they" is ambiguous – it could refer to the family or to the couple.
(A) This choice is incorrect as it repeats the original sentence.
(B) This choice incorrectly uses the relative pronoun "that" to refer to a group of people. Additionally, the pronoun "they" is ambiguous - it could refer to the family or to the couple.
(C) The use of the object pronoun "whom" makes "a girl and her family" the object of the clause "a gentile Dutch couple hid;" however "a girl and her family" are the subject of the next clause "were eventually discovered." This is a mismatch.
(D) CORRECT. It correctly uses the pronoun "who" to refer to a girl and her family. Additionally, the phrase "by a gentile Dutch couple" is placed immediately after "who were hidden" to clarify the meaning. Finally, the ambiguous pronoun issue is avoided altogether.
(E) The pronoun "they" is ambiguous - it could refer to the family or to the couple.

The original sentence contains several errors. First, "carbon monoxide levels in the atmosphere" is wordy. Second, "grew by enough of an increased percentage" is wordy and redundant. Third the singular pronoun "it" incorrectly refers to the plural "levels". Fourth, the final clause of the sentence--"and it caused the average surface temperature to rise"--is disjointed from the main clause.
(A) This choice is incorrect as it repeats the original sentence.
(B) This choice uses the unnecessarily wordy phrase "increased by enough of a percentage."
(C) CORRECT. The sentence is made more concise by rewriting "carbon monoxide levels in the atmosphere" as "Levels of atmospheric carbon monoxide" and "grew by enough of an increased percentage" as "increased sufficiently." The choice also eliminates the pronoun "it" from the sentence and reworks the final clause--"causing the average surface temperature to rise"-- as a modifier, thereby more clearly connecting it to the main clause.
(D) This choice uses the unnecessarily wordy phrase "increased by a sufficient percentage." It also uses "which" to refer to the action of the preceding clause, though "which" grammatically refers only to the immediately preceding noun (in this case, "Earth").
(E) This choice alters the position of during the twentieth century" and thereby changing the meaning of the sentence. In this choice "during the twentieth century" modifies the carbon monoxide levels instead of describing when those levels "increased." This distorts the meaning by leaving open the possibility that twentieth century carbon monoxide levels "increased enough" during some other time period (e.g., the 21st century).

The original sentence begins with a modifier ("having lived in Tahiti...") that clearly describes Paul Gauguin. Yet, the subject of the main clause is the impersonal "it". We need to find a choice that makes Gauguin himself the subject of the main clause. Moreover, the clause "where life was slow and relaxed" logically modifies Tahiti, though it's placement in the sentence modifies "several years". We need to find a choice that places this modifier after Tahiti. Finally, "upon returning" is awkward. "Upon his return" would be better.
(A) This choice is incorrect as it repeats the original sentence.
(B) This choice incorrectly uses "it" as the subject of the opening modifier "having lived in Tahiti . . .” Additionally, it uses the awkward phrase "upon returning."
(C) The modifier "where life was slow and relaxed" incorrectly modifies "years" instead of "Tahiti."
(D) CORRECT. "Paul Gauguin" is placed as the subject of the opening modifier "having lived in Tahiti." Additionally, the modifier "where life was slow and relaxed" is correctly placed next to its subject, "Tahiti."
(E) The phrase "because of the hectic pace" is left dangling at the end of the sentence; it is unclear that Paris is the subject of this phrase.

The original sentence contains several errors. First, the construction "by hiring more teachers and an increase in the amount of funding for books" is not parallel. We have a verb phrase paired with a noun. It would be better to have two verb phrases or two nouns, since both play the same role in the sentence. Second, "doing this" is
incorrect. A verb phrase cannot be replaced by a pronoun such as "this" or "it". Instead, it must be replaced by "so". For example, "I enjoy swimming at night, but doing so is dangerous" is preferable to "I enjoy swimming at night, but doing it is dangerous." Finally, the "amount of funding" is somewhat wordy and could be replaced by the more concise "funding."
(A) This choice is incorrect as it repeats the original sentence.
(B) CORRECT. It contains two parallel verb phrases, "hiring more teachers" and "increasing funding for textbooks and other supplies." Additionally "doing so" correctly replaces "doing this" and the concise "funding" is used in place of "amount of funding."
(C)The noun phrase "a hiring of more teachers" is not parallel with the verb phrase "increasing the amount of funding for textbooks and other supplies." Additionally, "amount of funding" is wordy.
(D) This choice incorrectly uses "doing this" instead of "doing so" to refer back to the verb phrase "hiring . . ."
Additionally, "amount of funding" is wordy.
(E) The verb phrase "hiring more teachers" is not parallel with the noun phrase "an increase in funding for textbooks and other supplies."

The original sentence begins with a modifier ("starting at age four") that describes Mozart. Yet, the subject of the main clause is Mozart's father. We need to find a choice that makes Mozart himself the subject. Moreover, the pronoun "him" has no grammatical antecedent, since it is meant to refer to Mozart despite the fact that Mozart is not actually present in the sentence (we have "Mozart's father" instead). Finally, the pronoun "his" is somewhat ambiguous: does it refer to Mozart (who, again, is not in the sentence) or to his father?
(A) This choice is incorrect as it repeats the original sentence.
(B) "Mozart's father" serves illogically as the subject of the opening modifier "starting at age four." Additionally, the pronoun "his" is ambiguous in that it could refer to the boy or the father.
(C) CORRECT. "Mozart" is correctly placed as the subject of the opening modifier "starting at age four." Additionally, the phrase "his own" clarifies that the musical talents in question are those of the subject, Mozart.
(D) This choice incorrectly uses the verb "was," which does not match the ongoing nature of the modifier "starting at age four." Additionally, the pronoun "his" is ambiguous in that it could refer to Mozart or his father.
(E) "Mozart's father" serves illogically as the subject of the opening modifier "starting at age four." Additionally, the
pronoun "him" has no grammatical antecedent, since it is meant to refer to Mozart despite the fact that Mozart is not actually present in the sentence (we have "Mozart's father" instead).

The original sentence contains several errors. First, the preferred idiom is "forbid X to do Y" and not "forbid X from doing Y". Second, the placement of the adverbial modifier "for the next three years" suggests that it modifies "link." However, the legislation does not forbid an Internet connection that "links" for the next three years; it "forbids" for the next three years raising Internet connection taxes.
(A) This choice is incorrect as it repeats the original sentence.
(B) This choice incorrectly uses "forbid X from doing Y" instead of the idiomatic "forbid X to do Y."
(C) CORRECT. This choice correctly uses the idiom "forbids X to do Y." Additionally "for the next three years" is
correctly placed next to the verb it modifies, "forbids."
(D) This choice creates an awkward sentence by using "forbidding to X Y" (where Y is the awkward noun "the
raising of taxes") instead of the idiomatic "forbid X to do Y."
(E) This choice incorrectly uses "forbid X from doing Y" instead of the idiomatic "forbid X to do Y."

The original sentence contains a clause beginning with "which" that logically describes the result of lower employment rates. However, as written, this clause seems to describe the result of "a drop in investment" because "which" modifies the noun just before it. We need to find a replacement that makes the causal relationship clear. Additionally, the phrase "causes people to cut consumer spending" is wordy and somewhat illogical since the people are the consumers. A more concise way to say this would be "causes cutbacks in consumer spending." Finally, the use of "back" is redundant, as it is implied by the word "cycle".
(A) This choice is incorrect as it repeats the original sentence.
(B) The use of "which" incorrectly suggests that "dropping investment" "causes people to cut consumer spending" when, in fact, the employment rates cause this phenomenon. Additionally, the phrase "causes people to
cut consumer spending" is wordy and the use of "back" is redundant, as it is implied by the word "cycle".
(C) CORRECT. This choice makes clear, through the use of the plural verb "cause", that the employment rates are responsible for the cutbacks in spending. Further it uses the concise phrase "cutbacks in consumer spending" and
eliminates the redundant word "back."
(D) This choice contains the wordy phrase "causing people to cut consumer spending" and the redundant phrase "lead back." Moreover, the words "causing" and "starting" illogically refer back to the economic recession. In fact, the falling employment rates, not the economic recession, cause the cutbacks in consumer spending and start the cycle of layoffs.
(E) The words "causing" and "starting" illogically refer back to the economic recession. In fact, the falling employment rates, not the economic recession, cause the cutbacks in consumer spending and start the cycle of layoffs.

The original sentence contains several errors. First, if we remove the clause "which is the more conventional approach for someone new to financial planning", we have "Instead of buying stocks and bonds, real estate has become increasingly..." This is not parallel. We need to find a replacement that indicates the alternative to buying
stocks and bonds. Second, on the GMAT "instead of" is reserved for nouns and "rather than" for verbs. So in this case, it would be better to say "Instead of stocks and bonds" or "rather than buy stocks and bonds."
(A) This choice is incorrect as it repeats the original sentence.
(B) This choice incorrectly uses "instead of" to introduce a verb ("buying").
(C) The phrase "rather than buying stocks and bonds" is not parallel to the phrase "real estate has become . . ."
(D) CORRECT. This choice correctly uses "rather than" to introduce the verb "buy" and sets up the proper
comparison between buying stocks and bonds and turning to real estate.
(E) This choice incorrectly pairs "instead of stocks and bonds" with "young people have shown . . ." This illogically implies that young people, instead of stocks and bonds, have shown an increasing attraction to real estate.

The original sentence contains the incomplete idiom "not only...but." The complete idiom is "not only...but also" (where "also" is not separated from "but"). Moreover, the combination of "require that" and "cannot" is incorrect. The construction "require that" necessitates the subjunctive mood for any verbs in the following clause.
(A) This choice is incorrect as it repeats the original sentence.
(B) CORRECT. The phrase "not only that principals . . . not share . . . but also that they not buy or sell" is an
idiomatic and parallel structure ("not only that x not y but also that x not z"). Additionally, the verb phrase "not share" is correctly in the subjunctive mood.
(C) The verb phrase "cannot buy or sell" is in the indicative mood, not in the subjunctive mood (which is necessary for verbs following the construction "require that"). Additionally, the words "but" and "also" are separated by the words "that they", unnecessarily breaking the idiom "not only . . . but also."
(D) The verb phrase "are not allowed" is in the indicative mood, not in the subjunctive mood (which is necessary for verbs following the construction "require that").
(E) The verb phrases "cannot share" and "cannot buy or sell" are in the indicative mood, not in the subjunctive mood (which is necessary for verbs following the construction "require that"). Additionally, the words "but" and "also" are separated by the word "they", unnecessarily breaking the idiom "not only . . . but also."

The subject of the original sentence is "what", which can be singular or plural depending on the context. In this case, in the opening clause "what concern scientists", the plural verb "concern" follows "what." Additionally, "what" serves as the subject of the main clause, "what . . . are the risks." If we flip this around, we get "the risks are . . . what." The plural noun "risks" forms the complement of "what." Thus, we have a situation where the verb of the what-clause ("concern") and the complement of the main clause ("the risks") are both plural; thus, the verb of the main clause should also be plural. The original verb "are" is therefore correct. However, the original sentence is incorrect because the second half of the sentence is not structurally parallel. The first and third risks are introduced using the word "that" while the second risk is not.
(A) This choice is incorrect as it repeats the original sentence.
(B) This choice incorrectly uses the singular verb "is" when the word "what" acts as a plural subject in this context.
(C) CORRECT. The main clause uses the plural verb "are" and each of the three risks is introduced with the word "that", thereby creating a parallel structure.
(D) This choice incorrectly uses the singular verb "is" when the word "what" acts as a plural subject in this context. Additionally, the second half of the sentence is not structurally parallel. The first and third risks are introduced using the word "that" while the second risk is not.
(E) The three risks are not written in parallel form. The first risk is introduced by the preposition "of" (the risk of polar ice caps. . .). The preposition "of" is also implied in the second (the risk of seas . . .). However, the third risk is introduced with the preposition "that" (the risk that violent weather patterns. . .).

The original sentence begins with the modifier "Famed for his masterful use of irony,"  which requires a person as its subject. However, in the original sentence, "many of Guy de Maupassant's short stories" is the subject. Moreover, the phrase "due to the author slowly revealing" is awkward.
(A) This choice is incorrect as it repeats the original sentence.
(B) The pronoun "he" must have a person as its antecedent, yet there is no person in the sentence. Remember that "he" cannot refer to "Guy de Maupassant" here, since the name is part of a possessive phrase: "Guy de Maupassant's short stories". The author himself is not grammatically present in the sentence.
(C) The opening modifier "famed for using irony in a masterful way" incorrectly modifies "short stories" instead of Guy de Maupassant himself. It also contains the awkward phrase "because of the author slowly revealing."
(D) CORRECT. This choice remedies the flawed modifier by rewriting the sentence to avoid it. This choice also replaces the awkward phrase "due to the author's revealing" with "evidenced in the slow revelation."
(E) This choice incorrectly uses the pronoun "he" without a grammatical antecedent in the sentence.

The original sentence incorrectly pairs an infinitive ("to approach") with a clause ("that they should...") in the construction "either X or Y." Moreover, the use of "like" in the phrase "to approach mathematics like a creative activity" is incorrect. :"As" should be used instead.
(A) This choice is incorrect as it repeats the original sentence.
(B) While this choice does contain proper parallel structure, it incorrectly uses "like" instead of "as" in the phrase "to approach mathematics like a creative activity".
(C) CORRECT. The construction "either X or Y" requires parallelism between X and Y. In choice C, both X and Y are parallel infinitive phrases ("to approach . . ." and "to force . . .").
(D) This choice incorrectly pairs a clause ("that they should...") with an infinitive ("to approach") in the construction "either X or Y." (E) While this choice does create a parallel construction, it awkwardly begins the parallel elements with the words "that they" instead of the infinitive "to." Moreover, this choice incorrectly uses "like" instead of "as" in the phrase "to approach mathematics like a creative activity".

The original sentence contains several flaws. First, the past perfect "had been" is unnecessary here because there is only one past event. Second, "high enough" implies that the oxygen deprivation was a goal of the Incas. Third, "it" in this context is ambiguous: is it the altitude or the city that makes tourists sick? Finally, "sick with" is incorrect. It should be "sick from."
(A) This choice is incorrect as it repeats the original sentence.
(B) This choice incorrectly uses the past perfect "had been." Additionally, the pronoun "it" is ambiguous in this context and the phrase "so high of an altitude" is awkward.
(C) This choice incorrectly uses the phrases "high enough altitude" and "sick with."
(D) CORRECT. The simple past verb "was" correctly replaces the past perfect verb "had been." The phrase "such a high altitude" replaces "high enough altitude." The sentence is rewritten to avoid ambiguity by removing the pronoun "it." Finally, this choice uses the phrase "sick from" in place of the unidiomatic "sick with."
(E) This choice incorrectly uses the awkward phrase "so high of an altitude." Additionally, the pronoun "it" in this context is ambiguous.

The original sentence introduces the main clause with "though viewed from a distance", which sets up the expectation of a contradiction that never materializes.
For example, "Though sleepy, the child stayed awake" is correct, whereas "Though sleepy, the child may have eaten soup" is not. Also, "when viewed up close" is placed in such a way as to illogically suggest that the rings are composed of icy ringlets as a result of being viewed up close. Finally, "appear to be" is redundant.
(A) This choice is incorrect as it repeats the original sentence.
(B) This choice incorrectly introduces the main clause with "though." Additionally, the placement of "when viewed up close" illogically suggests that the rings are composed of icy ringlets as a result of being viewed up close.
(C) This choice incorrectly uses the redundant phrase "appears to be." Additionally, the use and placement of the words "when viewed up close, they are . . ." illogically suggests that the rings are composed of icy ringlets as a result of being viewed up close.
(D) CORRECT. This choice replaces "though" with "when" and shortens "appear to be" to "appear." Further, its use of the phrase "closer viewing reveals" clearly indicates that the close viewing only reveals (not causes) the
composition of the rings.
(E) This choice incorrectly introduces the main clause with "though." Additionally, the placement of "if viewed up close" illogically suggests that the rings are composed of icy ringlets as a result of being viewed up close.

The original sentence contains several errors. First, the pronoun "it" is used to refer to the film, but the film has not been mentioned in the sentence. Instead "the sequel's poor critical reception" has been mentioned. This is not the same as the film, so the pronoun "it" has no grammatical antecedent and must be changed. Second, the
phrase "at least as good or even better than" is incomplete: there should be another "as" after "good". Third, the cinematography and acting are being compared to the "original". What is meant here is that the cinematography and acting in the sequel are as good as the cinematography and acting in the original. This must be changed.
(A) This choice is incorrect as it repeats the original sentence.
(B) The pronoun "it" has no grammatical antecedent and the phrase "at least as good or even better" is missing the second "as" after "good."
(C) CORRECT. This choice replaces "it" with "film", adds the missing "as", and makes clear that the acting and cinematography in the sequel are compared to the acting and cinematography in the original.
(D) The pronoun "it" has no grammatical antecedent and the phrase "at least as good or even better" is missing the second "as" after "good."
​(E) This choice introduces the possessive redundancy "those of the original's." One could say either "those of the
original" or "the original's", but using both is redundant.

The correct answer is E. The original sentence begins with a modifier "In response to growing demand for high-end vehicles" but this modifier has no logical subject within the main clause. Moreover, the pronoun "they" is ambiguous, as it could grammatically refer to either the interiors or to the cars. We know that the intended antecedent of "they" is the cars, so we need to find a choice that makes this clear. The only choice that remedies both issues without creating any new ones is E.

The correct answer is E. The original sentence contains a subject-verb problem: "the spectacular rise and fall of Napoleon" is a plural noun, but the corresponding verb "was" is singular. Moreover, "having been created" is unnecessarily complex. "Created by" would have been sufficient. Finally, it is not the "toppled monarchy" that
created the vacuum but rather the fact that the monarchy was toppled.
Choice A repeats the original sentence. Incorrect.
Choice B does not correct the subject-verb problem. Incorrect.
Choice C corrects the subject-verb problem but not the "toppled monarchy" issue. Incorrect.
Choice D does not correct the subject-verb issue. Incorrect.
Choice E corrects all the problems without creating any new ones. Correct.

The correct answer is D. The subject of the original sentence is "the mountain cornfloss," which is singular. However, the main verb is "grow," which is plural. We need to replace "grow" with "grows". Moreover, "thought of as being" is wordy and awkward. We need to find a more elegant way to phrase this. Choice D corrects the subject-verb issue and also finds a more economical phrasing in "and thought to be".

The correct answer is A. The original sentence contains no errors.
Choice B changes the meaning from "may actually increase" to "actually increases". Incorrect.
​Choice C is wordy and awkwardly phrased. Incorrect.
Choice D is wordy and awkwardly phrased. Incorrect.
Choice E is wordy and awkwardly phrased. Incorrect

The original sentence uses the verb singular verb "is" with the plural noun "western states". Moreover, the phrase "the more people that move to western states" is not parallel with "the more pressure on water resources becomes increasingly great." These two parts of the idiomatic construction "the more x, the more y" need to be in
the same form. We need to find a replacement.
Choice A is the same as the original sentence. Incorrect.
Choice B repeats the subject-verb mistake of the original and does not rectify the parallelism issue. Incorrect.
Choice C makes the parallelism even worse by beginning with a phrase "with more people moving to western states" that is not capable of sustaining the "the more x, the more y" construction. Incorrect.
Choice D avoids the subject-verb problem but does not remedy the parallelism issue, since "the more that people move" is not parallel with "the greater the pressure on water resources becomes". Incorrect. Choice E remedies the subject-verb problem and deals with the parallelism issue with the pair of phrases "the more people move to western states" and "the greater the pressure on water resources becomes." Correct.