An agreement question tests whether you can match a verb to its true subject despite extra nouns nearby. First, sort the forms by number: singular for one thing, plural for more than one. Then put who or what in front of the verb to find its subject, crossing out phrases that only add details. The verb matches the true subject, not nouns inside those phrases. Use it or they with each verb form to check the match.
Hints
- Hint 1
The blank comes before what scholars can do. Ask what gives them that ability, and look for its name earlier in the sentence.
- Hint 2
Look at the phrase between the commas. Does it name another subject, or add information about the subject already named?
- Hint 3
After setting aside the describing phrases, try replacing the subject with it or they. Which pronoun stands for the subject itself?
Step-by-step
Sort the forms, then find the subject
Step 1Sort by number
Start with the verb forms: allow, have allowed, and were allowing all fit after they, so they’re plural. In have allowed and were allowing, the helpers have and were show that number. The subject of the missing verb makes it possible for scholars to trace the movements of female itinerants. So check number rather than tense and find that subject next.
- Step 2
Look past the diaries
What gives scholars the ability to trace those movements? Start with An extensive archive, and set aside of nineteenth-century women’s travel diaries, which tells us what the archive contains. The diaries don’t control this verb, because they sit inside that describing phrase. That leaves the archive, but we still need to check whether the phrase between the commas adds another subject.
- Step 3
Check what the database adds
Does along with a searchable database of maritime records make the subject plural? The words along with add information about the archive; they don’t join two subjects the way and does. The commas set this added phrase apart, so we can cross out the database and the records it contains without removing the sentence’s subject. The database isn’t a second subject, which means the archive alone decides which verb form we need.
- Step 4
Match the singular subject
Can we replace An extensive archive with it or they? An archive is one thing, so its verb must be singular. The short check is it allows, which means allows matches the archive. Choice B.