Subject-Verb agreement comes naturally to native speakers of English. Native speakers, and fluent non-native speakers for that matter, know that it’s Jack runs and Jack and Jill run, not Jack run and Jack and Jill runs. Of course the writers of the GMAT try their best to confuse the issue. Their favorite trick is hiding the subject.
It’s important to keep in mind that we can only hold a limited number of words verbatim in our short term memory. If you don’t believe me, close you eyes and try to say the previous sentence verbatim. Consequently, if the subject and the verb are separated by more than a few words agreement can get tricky.
Most of spoken and written English follows Subject-Verb-Object (SVO) sentence structure. Many of the GMAT sentence correction prompts follow Subject-Abunchofotherstuff-Morestuff-Evenmorestuff-Verb-Object (SV………..O) sentence structure. Usually the stuff between the subject and verb contains lots of nouns and it’s easy to become confused about which noun the verb should agree with.
The little league baseball diamonds on the other side of the park Verb also used for the adult slow-pitch softball games.
Unfortunately, most people have a tendency to make verbs agree with the nearest noun, in this case park – a singular noun. The subject is really baseball diamonds – a pural noun phrase – so the verb should be are.
In our example above the confusion arises from a prepositional phrase – on the other side of the park. The GMAT can also trick you by starting sentences with modifying phrases or prepositional phrases that cannot stand alone as sentences:
In English Grammar and Useage Mark Lester and Larry Beason offer this quick and dirty trick for finding lost subjects:
“Jump from the verb back to first eligible noun in the clause or sentence, ignoring any nouns or pronouns in introductory phrases. Test that noun for agreement.”
It’s important to skip prepositional phrases when you’re moving backwards looking for the subject: ignore things like, on the beach, at dinner, after breakfast, before the game, under the table, etc. These phrases may contain nouns that agree with the verb but they are not subject phrases.
Lost subject problems in the 2015 official guide: 3, 7, 30, 36, 61, 79, 83, 107, 133, and 140.
Keep in mind that agreement is probably not the only thing to consider in each of the problems. Almost all SC problems address 2 or 3 errors.