An agreement question tests whether a verb matches its subject, even with other nouns nearby. First, sort the forms by number by trying each after it and they. Then ask who or what the verb is about, setting aside phrases that compare or describe. Match the true subject: one thing takes a singular verb, and more than one takes a plural verb. Nearby nouns don't control the verb unless they're its subject.
Hints
- Hint 1
Look at the comparison at the start. Where does it end, and which words before the blank remain outside it?
- Hint 2
Set aside the opening comparison and replace the remaining subject with it or they. Try that pronoun with each verb form.
Step-by-step
Sort the forms, then find the subject
Step 1Sort the verb forms by number
Try the verb forms after it and they to sort them by number. What do treat, are treating, and have treated have in common? Each works with they but not it, so each fits a plural subject, meaning more than one person or thing. Their tense differences can wait, because the blank's verb must match the subject that uses time travel not as a mere plot device.
- Step 2
Find the true subject
Set aside Unlike the novels that precede it, to see which words before the blank are left outside the comparison. Does mentioning several novels make the blank's subject plural? No, because those novels belong to the opening comparison and already have their own verb inside it. After the comma, Octavia Butler’s tells us whose book it is, while Kindred names the book the sentence describes. The true subject is the title, so neither the earlier novels nor the author controls the blank's verb.
- Step 3
Match one novel to its verb
Does Kindred name one thing or more than one? It names one novel, so we can replace the subject with it. For the present tense of treat, one thing takes the -s form, so the short version is it treats time travel, and treats fills the blank. Choice D.