An agreement question tests whether you can match a verb to its subject: one thing takes a singular verb, and several things take a plural verb. Sort the choices by number using it for one thing and they for several. When commas separate extra information, find the true subject by setting that information aside and asking who or what the verb is about. Match that subject’s number, because a nearby noun may belong to extra information instead.
Hints
- Hint 1
Look at the phrases separated by commas. Which words name the subject, and which words describe it?
- Hint 2
Replace the true subject with it or they. Which verb form works with the pronoun you chose?
Step-by-step
Sort, find the subject, and match
Step 1Sort the verbs by number
The blank leads into a frequent target of space telescopes, so its verb must match the subject’s number: one thing or more than one. Start by sorting the choices by number. Which forms work after they? The forms are, have been, and were do, so they’re plural.
- Step 2
Set aside the describing phrases
What does the sentence say telescopes often study? Set aside along with its many moons, which adds information about Saturn but doesn’t join another subject the way and would. The opening words, Known for its dazzling rings, also describe Saturn rather than name a second subject. What’s left is Saturn followed by the blank, so the planet is the true subject, not the moons.
- Step 3
Match the verb to one planet
Saturn names one planet, so replace that subject with it. Which verb works in the shorter version? We say it is, because a singular subject takes a singular verb, so is completes the sentence. Choice A.