GMAT Sentence Correction: Subject-Verb Agreement

Subject-verb agreement may seem very basic, but it will most certainly be tested on the GMAT sentence corrections. You can apply many of the same considerations as pronoun-antecedent agreement for these questions. For a more complete overview of subject-verb agreement let’s look at some examples below.
 

You must be careful to distinguish singular nouns from plural ones, even when the test-makers have made that tricky. For instance, check out the example sentence below; there’s a mistake. The subject of that sentence is “[s]ubject-verb agreement,” which is singular, but the verb, “pose,” is plural. Because the plural “corrections” is placed between them, the plural verb SOUNDS right, but is in fact incorrect. Let’s look at a couple more examples:
The team of soccer players are represented by their mascot, a wild boar.
This sentence demonstrates the same common trick, which is that a singular subject (team) is associated with a plural noun (players); a plural verb (are) is then placed next to that plural noun, and the unwary test-taker, relying on his or her sense of what “sounds right,” is lulled into thinking that the sentence is correct as written.
Incidentally, there’s a second, similar issue here: the pronoun-antecedent monster rears its ugly head.  While the test is busy tricking you into thinking that “team of soccer players” agrees with a plural verb, it also throws in a plural pronoun, “their.” The correct possessive pronoun for a singular entity like a team is “its.” The corrected version of the sentence above might therefore look like this:
The team of soccer players is represented by its mascot, a wild boar.

Another trick that is used to cause subject-verb agreement confusion is the insertion of a modifying phrase between the subject and verb in order to distract from the proper agreement. An example of that would be a sentence like this:
A yoga studio, which is offering a wide variety of classes, are opening in my neighborhood.
The subject here is “[a] yoga studio,” which is singular. The phrase “which is offering a wide variety of classes” is offset by commas, which tells us that the information is not essential to the meaning of the sentence and is instead a modifying phrase. The best way to check subject-verb agreement in a sentence like this is by “lifting out” that modifying phrase and reading the sentence without it. Thus, we can read it like this:
A yoga studio are opening in my neighborhood.
Now we can see much more clearly that the singular subject does not agree with the plural verb. The correct singular verb for this sentence would be “is,” not “are.”

How do we handle it, though, when the GMAT throws a more complicated sentence at us? The key is to break it up into bite-sized pieces and address each of them individually until you can clearly identify any subject-verb agreement problems. Here’s an example:
Despite the residents’ requests, the Homeowner’s Association Executive Board, which is made up of five members of the organization, haven’t issued a warning to those neighbors who have flouted the rules regarding lawn maintenance.
The two modifying phrases here—“[d]espite the residents’ requests” and “which is made up of five members of the organization”—obscure the subject and the verb, and make their disagreement more difficult to identify. Again, “lifting” those phrases out and reading around them can help. However, here we also have the issue of a singular noun (the Homeowner’s Association Executive Board) that sounds plural, since it’s made up of multiple people, but is in fact singular. The plural verb “haven’t” is therefore incorrect in the sentence as written. There are a couple of ways to fix this, each of them equally viable as an answer choice on the GMAT.
Despite the residents’ requests, the Homeowner’s Association Executive Board, which is made up of five members of the organization, hasn’t issued a warning to those neighbors who have flouted the rules regarding lawn maintenance.
Despite the residents’ requests, the five members of the Homeowner’s Association Executive Board haven’t issued a warning to those neighbors who have flouted the rules regarding lawn maintenance.
In the first version, we replace the plural verb with a singular one; in the second, the singular subject becomes plural by incorporating into it the modifying phrase. Either one works as a correction here.
Remember that on GMAT sentence corrections, it pays to keep your eyes open for errors that “sound” fine AND your mind open for unexpected ways to correct those errors.