GMAT Sentence Correction Practice Questions: Verb Forms and Parallelism
Two related error types on GMAT Sentence Correction questions are verb forms and parallelism. The form of a verb must be logical and appropriate for the timing of the performance of the verb. And verbs in a list, being performed by the same subject, should be in the same form and tense. A sentence that doesn’t follow this rule has a parallelism problem. Even if this language about verb forms and tenses is somewhat unfamiliar to you, you can probably spot sentences that have a verb form or parallelism error.
GMAT Sentence Correction Practice Question
Let’s look at an example from the Official Guide that has a verb form or parallelism error:
Travelers from Earth to Mars would have to endure low levels of gravity for long periods of time, avoiding large doses of radiation, plus contending with the chemically reactive Martian soil, and perhaps even ward off contamination.
(A) Mars would have to endure low levels of gravity for long periods of time, avoiding large doses of radiation, plus contending
(B) Mars would have to endure low levels of gravity for long periods of time, avoid large doses of radiation, contend
(C) Mars, having to endure low levels of gravity for long periods of time, would also have to avoid large doses of radiation, plus contending
(D) Mars, having to endure low levels of gravity for long periods of time, avoid large doses of radiation, plus contend
(E) Mars, who would have to endure low levels of gravity for long periods of time, avoid large doses of radiation, contend with
What is this sentence trying to do? It is trying to list things that travelers from Earth to Mars would have to do. As soon as the first verb used is endure, you should be looking for the rest of the verbs to match this form. Also notice that the final verb in this last – which comes after the underlined portion – is ward off. We should see this:
. . . endure ______, avoid ______, contend with _____, and ward off _____.
We can’t change the form of the first three verbs, because they must all match ward off. Answer choice E comes close, but even though it has the four verbs endure, avoid, contend with, and ward off, it has no main verb!
The use of the word who after the introduction Travelers from Earth to Mars makes all of this information about those travelers parenthetical. It’s just sided information about those travelers; it’s not in the main flow of the sentence. But the sentence just ends without ever coming back to what it was really trying to say about those travelers!
Here are some examples of sentences that are incomplete because they commit the same sin:
- The car on the lot, which had been there since it was abandoned by its owner last April.
- Simon’s sandwich, which had smoked turkey, provolone, tomatoes, pickles, and mayonnaise.
- The drummer, who had previously worked with such famous musicians as Wynton Marsalis and Alicia Keys.
None of these sentences ever gets around to what it was trying to say. Each of them leaves us hanging without a main verb. The verbs in the relative clauses beginning with relative pronouns like which and who are not main verbs. Look out for this error!
The more you practice Sentence Correction and the more time you spend reading sophisticated writing, the more you’ll develop a “main flow” sensor that runs in the background and tells you when you’re in the “main flow” of the sentence and when you’re in an interrupting, parenthetical portion. Commas are versatile, but one of their main functions is to set off interrupters from the “main flow” of the sentence.
Coming back to the problem above, the correct answer is B. The verbs are parallel in form (endure, avoid, contend with, and ward off), and they are in the main flow of the sentence. Also note that there must always be an and before the final verb in a list. In this question, the and is outside the underlined portion and not under consideration. But some incorrect answer choices will sneakily omit this necessary and. When you recognize a verb parallelism question, make sure you see the and before the final verb.
GMAT Sentence Correction Practice Question
Here’s another verb form question:
Because it regarded the environmentalists as members of an out-of-state organization, the city council voted that they are denied permission for participating in the parade.
(A) that they are denied permission for participating
(B) that they be denied permission for participating
(C) denying them permission for participation
(D) the denial of permission that they participate
(E) to deny them permission to participate
Here we aren’t listing verbs being performed by the same subject. Instead, the forms of the verbs in the underlined portion are simply unidiomatic and incorrect.
Here we should be immediately looking for the choice that begins with to deny, since this is the idiomatically correct continuation after the verb voted. Thankfully, our only option is answer choice E, which also ends properly with permission to participate. This is better than permission for participating from choices A and B, and it is certainly better than what we see in choices C and D.
GMAT Sentence Correction Practice Question
Example of sentences with the same grammar error
To show that it is serious about addressing the state’s power crisis, the administration has plans for ordering all federal facilities in California to keep thermostats at 78 degrees Fahrenheit and shutting down escalators during electricity shortages this summer.
(A) has plans for ordering all federal facilities in California to keep thermostats at 78 degrees Fahrenheit and shutting
(B) has plans to order that all federal facilities in California are keeping thermostats at 78 degrees Fahrenheit and shutting
(C) is planning on ordering all federal facilities in California to keep thermostats at 78 degrees Fahrenheit, and they will shut
(D) is planning to order that all federal facilities in California are keeping thermostats at 78 degrees Fahrenheit and shut
(E) is planning to order all federal facilities in California to keep thermostats at 78 degrees Fahrenheit and shut
Sometimes it is fruitful to notice exactly where the underlined portion begins and ends. In this question, it ends immediately after the verb shutting. Even outside this article, that fact should make you think, “Ah, a verb form question.” If you have any doubt, you can scan the answer choices in a few seconds and see that the form of shutting does indeed change to shut in answer choices C, D, and E.
In the given version of the sentence, the form of shutting parallels ordering from earlier in the sentence. This is a problem, because it would lead us to think that the administration – not the federal facilities – will be shutting down the escalators. A sentence like this one can be tricky because technically, nothing about it is grammatically incorrect. You must recognize illogical sentences as well as incorrect and unidiomatic sentences.
The administration had plans for ordering . . . and for shutting down . . .
But this isn’t what the sentence really means to say. It should be the federal facilities, not the administration, shutting down the escalators. Since this is true, we want to match the form of the other verb attached to those federal facilities: the verb keep.
. . . all federal facilities in California to keep . . . and (to) shut down . . .
Aside from this verb form issue, the phrase has plans for ordering in the given sentence is somewhat unidiomatic. Answer B uses the parallel forms keeping and shutting, but the tense of the verbs is illogical. There is no reason to say are keeping and are shutting (in the present progressive tense.)
Choice C awkwardly leads to the same problem as choice A; using the vague pronoun makes it sound like the administration itself – not the federal facilities – will be shutting down the escalators.
Choice D has a combination of the problems already discussed in answer choices A, B, and C. Choice E is correct. The verbs are parallel, and this parallelism links each verb to the intended subject. The administration does the ordering; the federal facilities do the keeping and the shutting.
GMAT Sentence Correction Practice Question
Here is a question involving a different kind of parallelism:
Over the next few years, increasing demands on the Chattahoochee River, which flows into the Apalachicola River, could alter the saline content of Apalachicola Bay, which would rob the oysters there of their flavor, and to make them decrease in size, less distinctive, and less in demand.
(A) which would rob the oysters there of their flavor, and to make them decrease in size,
(B) and it would rob the oysters there of their flavor, make them smaller,
(C) and rob the oysters there of their flavor, making them decrease in size,
(D) robbing the oysters there of their flavor and making them smaller,
(E) robbing the oysters there of their flavor, and making them decrease in size,
Did you spot the verb parallelism issue in the given sentence? The verbs rob and make are both linked to the idea in the previous phrase about the alteration of the saline content of Apalachicola Bay. We should expect to see this:
. . . which would rob . . . and make
But the given sentence uses to make instead of just make. To make doesn’t properly follow which would, and it doesn’t match the form of rob. Simply substituting make for to make, however, will not completely fix this sentence.
The entire construction beginning with which is incorrect. Technically the relative pronoun which should refer to the most recently mentioned noun: Apalachicola Bay. But that is not what this sentence means to say. It is the alteration of the salinity of the bay – not the bay itself – that will rob the oysters of their flavor.
Also, the underlined portion extends far enough to include the first member of the list at the end of the sentence. This is a list of adjectives, not verbs, but the same rules of parallelism apply! The adjectival phrases less distinctive and less in demand are not underlined and can’t be changed, so we must make the first member of this list match their form.
These are comparative adjectives, so the correct choice for the first member of this list is the comparative adjective smaller – not the verbal phrase decrease in size used in the given sentence. This narrows the selection to just two answer choices: B and D.
B is incorrect because make is the final verb in a two-member list, the other member being rob. Since make is the final member in this list, it needs to be preceded by the word and. Without this and, we expect a third verb paralleling rob and make, but the sentence never provides such a verb.
D is the correct choice. Choice D is also superior to choice B in that it begins with the participle robbing instead of the phrase and it would rob. The participle phrase is clearer because it conveys that the robbing and making are logical consequences of the alteration of the saline content of Apalachicola Bay. In such a construction, we may imagine the use of the word thereby in the sentence:
Over the next few years, increasing demands on the Chattahoochee River, which flows into the Apalachicola River, could alter the saline content of Apalachicola Bay, thereby robbing the oysters there of their flavor and making them smaller, less distinctive, and less in demand.
Writing the sentence with this inclusion of thereby would sound somewhat pompous and heavy-handed, but it’s a good way to demonstrate the preferability of the participle construction in this case.
GMAT Sentence Correction Practice Question
Here’s a related question:
About 5 million acres in the United States have been invaded by leafy spurge, a herbaceous plant from Eurasia with milky sap that gives mouth sores to cattle, displacing grasses and other cattle food and rendering rangeland worthless.
(A) States have been invaded by leafy spurge, a herbaceous plant from Eurasia with milky sap that gives mouth sores to cattle, displacing grasses and other cattle food and rendering
(B) States have been invaded by leafy spurge, a herbaceous plant from Eurasia, with milky sap, that gives mouth sores to cattle and displaces grasses and other cattle food, rendering
(C) States have been invaded by leafy spurge, a herbaceous plant from Eurasia having milky sap that gives mouth sores to cattle and displacing grasses and other cattle food, rendering
(D) States, having been invaded by leafy spurge, a herbaceous plant from Eurasia with milky sap that gives mouth sores to cattle, displaces grasses and other cattle food, and renders
(E) States, having been invaded by leafy spurge, a herbaceous plant from Eurasia that has milky sap giving mouth sores to cattle and displacing grasses and other cattle food, rendering
When the underlined portion is this long and complex, it is all the more important to proceed by diagnosing and correcting the given sentence. Dealing with each answer choice on its own will take too long and be too taxing.
The use of the participle forms displacing and rendering near the end of the underlined portion makes it sound like these things are logical consequences of the leafy spurge’s giving mouth sores to cattle! Insert the imaginary “thereby” in order to see this more clearly:
About 5 million acres in the United States have been invaded by leafy spurge, a herbaceous plant from Eurasia with milky sap that gives mouth sores to cattle, thereby displacing grasses and other cattle food and rendering rangeland worthless.
But of course, the displacement of grasses and other cattle food is NOT a logical consequence of those cattle getting mouth sores. The participle construction in the given sentence is inappropriate.
Let’s think about the logical relationships of the verbs.
Three things happen as a result of the leafy spurge invasion:
(1) Cattle get mouth sores
(2) Grasses and other cattle foods are displaced
(3) Rangeland is rendered worthless
(2) and (3) are not logical consequences of (1), as the given sentence indicates. Rather, (3) is the logical consequence of (1) and (2). Recognizing this is the quickest way to filter these answer choices. Leafy spurge gives mouth sores to cattle and displaces grasses and other cattle food, thereby rendering rangeland worthless. You should scan the answer choices for these logical verb forms. Here they are in isolation:
(A) gives, displacing, rendering
(B) gives, displaces, rendering
(C) gives, displacing, rendering
(D) gives, displaces, renders
(E) giving, displacing, rendering
The correct answer choice is B.
GMAT Sentence Correction Practice Question
We’ll conclude with two shorter questions. Here’s the first:
Five hundred million different species of living creatures have appeared on Earth, nearly 99 percent of them vanishing.
(A) Five hundred million different species of living creatures have appeared on Earth, nearly 99 percent of them vanishing.
(B) Nearly 99 percent of five hundred million different species of living creatures that appeared on Earth have vanished.
(C) Vanished are nearly 99 percent of the five hundred million different species of living creatures that appeared on Earth.
(D) Of five hundred million different species of living creatures that have appeared on Earth, nearly 99 percent of them have vanished.
(E) Of the five hundred million different species of living creatures that have appeared on Earth, nearly 99 percent have vanished.
The participle form of vanishing is inappropriate for the timing of this verb, or at least unclear. We can’t tell for sure if these species are in the process of vanishing or if they have already vanished. Presumably, the sentence is trying to say that these species have vanished.
A quick glance at the answer choices shows us that B, D, and E do in fact end with this more appropriate form (the perfect tense).
Choice B illogically changes have appeared to just appeared, making it sound as if no more species of living creatures will ever appear on Earth.
Choice D has a redundancy problem, beginning with Of and later including the equivalent phrase of them. Also, choices B and D both lack the definite article the before five hundred million different species.
Choice E, the correct answer, makes it clear that these five hundred million are all the species of living things that have appeared on earth so far.
GMAT Sentence Correction Practice Question
Here’s a final question:
The English physician Edward Jenner found that if experimental subjects were deliberately infected with cowpox, which caused only a mild illness, they are immune from smallpox.
(A) which caused only a mild illness, they are immune from
(B) causing only a mild illness, they become immune from
(C) which causes only a mild illness, they are immune to
(D) causing only a mild illness, they became immune from
(E) which caused only a mild illness, they would become immune to
Sentence Correction is about finding the best path of eliminations to answer questions quickly and easily. In this case, the phrase immune from is unidiomatic and incorrect. It should be immune to. Recognizing this narrows the field to just two answer choices.
Once you see that answer choices A, B, and D, end with immune from, you don’t have to think about anything else in them. When you first see a new Sentence Correction question, you should approach it like this. Later on, you should look at those answer choices you eliminated and try to identify everything that is wrong with them.
This habit gets you more mileage out of each question and sharpens your skills of error recognition and labeling. You want to do everything possible to develop your Sentence Correction thinking from fuzzy and intuitive to precise and explainable.
In this question, answer E is better than answer C because it uses the subjunctive moods. Verbs don’t just have tenses, they also have moods. The subjunctive mood, which using helping words like could and would, is appropriate for hypothetical scenarios, like the one here: if experimental subjects were deliberately infected with cowpox.
This makes the subjunctive mood of choice E (they would become immune) more appropriate than the indicative mood of choice C (they are immune). Answer choice E is correct.
Remember that English sentences are built around verbs. Giving attention to the forms and the logical relationships of these verbs is the best way forward in many Sentence Correction questions.