A verb form question with several verbs tests whether the blank needs a main verb and what its subject is. Sort the forms: an -ing form needs a helper to be a main verb, and a to form can't be one alone. Then read to the period, setting aside verbs inside other parts of the sentence. If the blank needs a main verb, find its whole subject: one thing takes a singular verb, and more than one takes a plural verb.
Hints
- Hint 1
Start with the opening That and read up to the blank. Look for the whole sentence's subject, rather than stopping at a noun inside the opening words.
- Hint 2
Set aside the words between the dashes, then ask which verbs belong to the groups beginning with That and that. Does either group supply the main verb of the whole sentence?
- Hint 3
Try replacing the whole subject with it or they. Which pronoun stands for what the sentence is really about?
Step-by-step
Sort, count, and match the whole subject
Step 1Sort the verb forms
Sort the offered forms by whether they can be a main verb, the verb that says what a subject does or is. An -ing form needs a helper, and a to form can't be a main verb on its own. Now read from That the octopuses reopened jars to the period to ask: does the whole sentence already have its main verb?
- Step 2
Find the whole subject
The opening That the octopuses reopened jars presents something that happened. What is the sentence about: the animals, or that reported fact? The whole reported fact is the subject, and the opening words form a clause, a group with its own subject and verb. The detail starting even when the jars contained no food sits between dashes, so set it aside while finding the main verb.
- Step 3
Count the main verbs
Does that whole subject already have a main verb? The verbs reopened and had watched belong inside the opening subject clause, while the verbs after the blank belong to the clause beginning that the animals were not merely following odor cues. Neither group gives the whole sentence its main verb, so the blank must supply it. The bare -ing form suggesting and the to form to suggest can't do that.
- Step 4
Match the verb to the whole fact
A whole clause used as a subject counts as one thing, even if it contains plural nouns. Shrink this subject to it: it suggests works, while are suggesting takes a plural subject, as in they are suggesting. The main verb suggests matches the whole fact. Choice B.