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    Sentence Correction
  I: Fundamentals
  II: Three-Step Method to the Sentence Correction Questions
III: Eight Types of Errors in the Sentence Correction Section  
A. Subject-Verb Agreement
B. Modifiers
C. Parallelism
D. Pronoun Agreement
E. Verb Time Sequences
F. Comparisons
G. Idioms
  IV: Sample Questions
  V: Advanced Work

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Eight Types of Errors in the Sentence Correction Section

The GMAT tests only a limited number of grammar error types.
Therefore, you only need to learn a limited number of grammar rules – you don't need to master every grammatical and stylistic rule of Standard Written English to do well on the GMAT.

A. Subject-Verb Agreement
B. Modifiers
C. Parallelism
D. Pronoun Agreement
E. Verb Time Sequences
F. Comparisons
G. Idioms

A. Subject-Verb Agreement

Subjects and verbs must agree. The 'subject' of a sentence is the noun to which the verb in the sentence refers, and so the two must always agree in number: singular subjects must be paired with singular verbs; and plural subjects, with plural verbs. Though it may sound simple, the GMAT uses tricky constructions and phrasings that make these questions seem far more complicated, and confusing, than they actually are.

Test writers will try to fool you by writing unusual phrases that make it difficult to tell if the subject is singular or plural. Below, you'll find a list of rules and tips for subject-verb agreement that will assist you in making sense of confusing questions.

Subject-Verb Agreement
Overview of this section:

1. Subject / verb separation
2. Collective nouns
3. Plural / singular
4. Neither / either
5. Or / nor
6. Subject / verb / object


1. A subject and verb may be separated by an accompanying phrase without changing the agreement.

The child, together with his grandmother and his parents, is going to the beach.

This sentence is grammatically correct. When a phrase sandwiched by commas comes between a subject and a verb, the subject and verb must still agree, even if the sandwiched phrase contains other nouns. The accompanying phrase "his grandmother and his parents" only provides extra information and does not alter in any way the grammatical relationship between the subject (the child) and the verb (is going).

Pay special attention to who or what is doing the action indicated by the verb, and make sure it agrees with the verb; ignore everything else.

Here is any easy way to handle this kind of "sandwich" agreement question. Take a look at the following sentence and decide whether it is correct or incorrect:

Frank, accompanied by his students, were at the studio.

There are three nouns in this sentence, and two verbs. To clarify which noun is the subject, and which verb it should agree with, cross out everything inside the commas:

The subject is the only noun in front of the crossed-out sandwich; the verb we're looking for is the only remaining verb in the sentence. After crossing out the sandwich, we are left with the following:

Does this make sense? No. Frank is only one person, and so the verb should be singular, not plural.

By crossing out the section inside the commas, we were able to see clearly that Frank, a singular proper noun, is the subject of the sentence, not his students. Thus, Frank was at the studio.

Incorrect: Frank, accompanied by his students, were at the studio.
Correct: Frank, accompanied by his students, was at the studio.


Not all subject-verb agreement questions will be "sandwiched", like the last two examples – the GMAT test writers have many kinds of tricks up their sleeves. Regardless of the form of the sentence, it is always crucial to keep track of the subject and verb.

Here's another form that subject-verb agreement questions can take:

His mastery of several sports and the social graces make him a sought-after prom date.

This sentence, like the two "sandwich" questions, tries to distract you from the singular subject by inserting plural nouns just before the verb. These questions can be more difficult, because there are no conveniently-placed commas to tell you what to cross out, but, once you've handled that, you can apply the same tactic used with the "sandwich" questions. In this case, the phrase to be crossed out is "of several sports and the social graces":

After crossing out the phrase, it is clear that the plural verb "make" does not agree with the singular noun "mastery" – the subject of the sentence. Thus:

Makes is the singular form of the verb to make.

Incorrect: His mastery of several sports and the social graces make him a sought-after prom date.
Correct: His mastery of several sports and the social graces makes him a sought-after prom date.

Click here for more hints and tips on tackling complicated "cross-out" questions.

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2. Collective nouns, such as family, majority, audience, and committee are singular when they act in a collective fashion or represent one group. They are plural when the members of the collective body act as individuals. Collective nouns will usually be singular in Sentence Correction sentences.

A majority of the shareholders wants the merger.

This sentence is grammatically correct – but confusing. To determine whether a confusing noun requires a singular or plural verb, it might be helpful to visualize what's actually going on in the sentence. Is the sentence talking about something that acts as a singular entity? Or is it talking about the individual elements within that entity?

In the sentence here, there is no indication that the sentence is referring to the individuals within the majority. The "majority" acts as one – as a singular entity - and therefore requires a singular verb, "wants."


The flock of birds is flying south.

Again, the "flock of birds" is referred to as a singular group – we're not talking about each bird's direction of flight, but the direction of the flock as a whole - thus it requires the singular verb "is," not the plural verb "are."

The team are always fighting amongst themselves.

This is an example of a collective noun that requires a plural verb. You will not see this very often on the GMAT, but it's useful to illustrate the necessity of reading the entire sentence and visualizing what it describes: while 'team' is often used as a singular collective noun, in this case, the sentence describes the fighting that occurs between the individual members of the team. "Team" therefore refers to several individual members, and requires a plural verb, "are," as a result.

The key to these questions is simplicity: recognize the collective noun, visualize what's going on in the sentence, and proceed. These questions are included in the GMAT not because they are especially difficult, but because test writers expect most students to be unfamiliar with the rules governing collective nouns. If you are, then you're already ahead of the game.

Click here for a list of collective nouns.

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3. Phrases separated by and are plural; phrases separated by or or nor are singular.
This is a hard-and-fast rule. Memorize it.

Because the names – Ted, John, I - are separated by the word "and", the plural form of the verb is used. Notice that this is a very straightforward grammatical construction: the subject is plural because it refers to more than one person (or place, or thing, or event), and plural nouns require plural verbs.

Because the names are separated by the word "nor", the singular form of the verb is used. This construction is the more complicated of the two: it looks very much like the 'and' construction, but means the opposite. The sentence tells us that Ted is not going, and John is not going either. Since neither one of the two is going, we must use a singular verb. If this seems confusing, think of the term "no one": would you say "no one are going"? Or "no one is going"? The latter is clearly correct. How can "nothing" be plural?

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4. Neither and either always take singular verbs when acting as the subject of a sentence.

When applied, this construction often strikes people as incorrect. It is not incorrect, but it is one of the grammatical conventions of written English that cannot be reasoned out from scratch. You must become familiar with this rule: memorize it, and use it.


In this sentence, "neither" is the subject, not the plural noun "rosebushes". "Neither" takes the singular verb "is".


In this sentence, the word "either" can be thought of as an abbreviation of the phrase "either one". Construed in this manner, it becomes quite clear that "us" is not the subject of the sentence – "either" is. The sentence therefore requires the singular verb "is".

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5. Neither/nor and either/or are a special case. If two subjects are joined by or or nor, the verb should agree with the subject that is closer to it.

If the conjunction nor appears in a sentence with neither; or the conjunction or with either, then the "neither/either" rule as stated above no longer applies. In these constructions, "neither" and "either" function as conjunctions, working in pairs with "nor" and "or" to join two subjects in the sentence. When this occurs, the verb agrees with whichever subject is closer to it. This rule must also be memorized.

This sentence contains two subjects: "supervisor," and "staff members." Because they are joined by the correlative conjunction "neither/nor," the verb agrees with the subject closest to it: "staff members," which is plural. The plural verb "were" is therefore correct.

This example is identical, grammatically, to the one above, except that the correlative conjunction joining the subjects is "either/or." The verb must therefore agree with the subject closest to it, which is "child," a singular noun. The proper verb form is the singular, "is."

Remember to apply this rule only when both items of the pairs "neither/nor" and "either/or" are present in the sentence.

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6. Be careful to choose the right subject in sentences in which the verb precedes the subject.

In some sentences you encounter, it may be difficult to discern which of several nouns is the subject. Nouns can function as subjects or objects, and we usually rely on their placement in the sentence to determine which is which. Such sentences follow the pattern SubjectVerb — Object.

Here is an example:

This sentence is straightforward: because the first noun in the sentence, dog, is followed by an active verb, ate, we know that the dog is performing the action indicated by the verb, and is therefore the subject of the sentence. Homework is the object.

Some sentences, however, will stray from this pattern. When all nouns in the sentence follow the verb, it can sometimes be very difficult to figure out which of those nouns is the subject.

Incorrect: There is many reasons why I can't help you.

Here, there are two verbs (there is and help) and three nouns (reasons, I, and you). Sandwiched between the first and second verbs are two nouns; another noun follows the second verb. If we look carefully at the sentence, we may notice that the clause "I can't help you" follows the traditional pattern, in which I would be the subject. We may therefore be tempted to decide that I is the subject of the sentence as a whole. However, why I can't help you is in fact a subordinate clause, or dependent clause, and functions here as a direct object.

Correct: There are many reasons why I can't help you.

The subject is the only noun that exists outside of the subordinate clause: "reasons." It is plural, and thus requires a plural verb, "are."

Click here for more confusing singular and plural words.

Final Tips
A quick summary of how to recognize subject-verb agreement errors. Look for:

A subject and verb separated by superfluous nouns ("the sandwich")
Collective nouns like majority, audience, family…
Phrases separated by conjunctions like and, nor, neither
Other confusing nouns like data/datum.

Click here for all extra subject-verb agreement hints and tips.

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Continue to B: Modifiers