An agreement question offers forms of one verb and tests whether that verb matches its subject. Sort the forms by number, even if they also differ in time. When extra words separate the subject from the blank, ask who or what the verb describes and cross out those extra words. One thing takes a singular form, as in it helps; more than one takes a plural form, as in they help. The nearest noun may not be the true subject.
Hints
- Hint 1
The blank belongs to the second sentence. Ask who or what the verb describes to find the subject of its verb.
- Hint 2
Mentally remove the words between the commas. Then check whether the phrase beginning with of names the subject or describes it.
Step-by-step
Sort, find the subject, and match
Step 1Sort the verb forms by number
Start by sorting the verb forms in the choices by number: one thing or more than one. What do the forms tell us? The form provide goes with they, and so do are providing and have provided, because the helpers are and have go with more than one. The blank needs a verb for giving evidence about the refreshments once sold to audience members, so the true subject decides the verb’s number. The different tenses won’t settle that match.
- Step 2
Find the subject past the extra words
Start with including two jars decorated with images of musicians, the extra information between commas, and cross it out. What remains before the blank? There’s still of the vessels, but that phrase tells us which group is meant rather than naming the subject itself, so cross it out too. The true subject is Each, which means each one taken alone and takes a singular verb. Even though researchers found many vessels, this sentence describes what each vessel does on its own.
- Step 3
Match the singular subject
Shrink Each of the vessels to it: which verb form can follow that singular pronoun? The check is it provides, so the present-tense form with -s fills the blank and makes the verb agree with each. Choice D.