A verb form question tests whether a verb does the right job and matches its subject. Sort the forms by number and job, then check whether the blank’s clause still needs a main verb. A main verb says what the subject does or is; an -ing form needs a helper for that job. Find the true subject past extra information between commas. With a third-person subject, one thing takes a singular verb, while more than one takes a plural verb.
Hints
- Hint 1
Read the second sentence to the period and check which verbs belong to clauses that add details. Do any of those verbs say what the sentence’s subject does?
- Hint 2
Cross out the words between commas, then look at the subject beside the blank. Would you replace that subject with it or they?
Step-by-step
Sort, find, and match
Step 1Sort the forms and check the main verb
Sort the forms: allow and have allowed work with they, while allowing can’t be a main verb on its own. Does the second sentence still need a main verb, the verb saying what its subject does or is? The verbs in which later influenced major court decisions and that cross state borders belong to clauses that add details, so the blank must supply the main verb.
- Step 2
Find the true subject
What gives the federal government this ability? Let’s cross out the extra information between commas, which later influenced major court decisions. That leaves This provision beside the blank, so the court decisions don’t control this verb. One provision is the true subject.
- Step 3
Match the verb to one provision
Now shrink This provision to it and test the main-verb forms. We say it allows, not it allow or it have allowed, so allows matches the singular subject. Choice C.