A verb agreement question tests whether a verb matches its subject in number. Sort the forms into singular and plural, then find the true subject of the blank. In a long sentence with several verbs, ask which subject belongs to each verb. One thing takes a singular verb, while more than one takes a plural verb, even when other nouns stand between subject and verb. The nearest noun may belong to a different part of the sentence.
Hints
- Hint 1
Start with the opening That and look for where the group it introduces ends.
- Hint 2
Find the verb that already belongs to the bubbles. Then ask whether those bubbles are also the subject of the blank.
- Hint 3
Replace the full subject of the blank with it or they. Does that subject name separate objects, or does it present a whole fact?
Step-by-step
Find the whole subject
Step 1Sort the verb forms by number
Sort the choices into singular and plural, since the forms differ in number as well as tense. The forms have supported, are supporting, and support go with a plural subject here; a present-tense form ending in -s goes with a singular subject. We need to find what gives evidence for materials scientist Laila Nasser’s conclusion.
- Step 2
Find the bubbles’ own verb
What do the bubbles do? Set aside unlike the roughly spherical bubbles in samples allowed to cool without rotation, which compares them with other bubbles. The remaining words say that the trapped bubbles align with spiral paths, so the bubbles already have their own verb. The later verbs describe the glass following those paths while the vessels were shaped, and don't finish the larger sentence.
- Step 3
Recognize the whole fact as the subject
What does the opening word That do? It introduces a clause, a group of words with its own subject and verb, and lets that whole clause serve as the subject of the larger sentence. The subject extends through as the vessels were shaped: it's the fact that the bubbles line up with the paths, not the bubbles alone. A whole clause used as a subject counts as one thing, even when its own subject is plural.
- Step 4
Match the verb to one fact
Which form goes with it when we shrink the clause beginning That the elongated bubbles? The short check is it supports Nasser’s conclusion, because supports is singular. The forms have supported, are supporting, and support all go with they here. Choice B.