An agreement question tests whether a verb matches a subject that’s one thing or more than one. Sort the forms by number: one thing takes an -s form, is, or has, while more than one takes the plain form, are, or have. If the blank follows that, ask which noun that refers to. Then cross out extra phrases and check that noun with it or they. A nearby noun may belong to a phrase rather than be the verb’s subject.
Hints
- Hint 1
The blank is in the part beginning with that. Ask which noun that part describes.
- Hint 2
The opening puts a location before lie. What would the opening say if you put its subject first?
- Hint 3
Cross out the words between commas and check whether the subject is one thing or more than one.
Step-by-step
Sort, find the subject, and match
Step 1Sort the forms by number
Start by sorting the verb forms by number, meaning whether they go with one thing or more than one. Illuminates, is illuminating, and has illuminated are singular forms: each works after it. The blank follows catacombs that, so we need the number of the noun that that stands for. The different tenses don’t settle that question.
- Step 2
Find what that stands for
Which noun does that stand for? Beneath the monument lie catacombs puts the subject after the verb, so flip the opening: the catacombs lie beneath the monument. The monument names the place, while the catacombs are the things located there. The following that begins a clause, a group of words with its own subject and verb, and points back to the catacombs. That’s the noun whose number controls the blank, even though it comes after lie.
- Step 3
Remove the extra phrase
Does together with a recently cataloged artifact collection make the collection part of the subject? No: together with adds extra information between commas, not a second subject joined by and. Cross that phrase out, and the describing part is about the catacombs alone. Since there’s more than one catacomb, the subject is plural, which means we can replace it with they.
- Step 4
Match the verb to they
Which form works after they, our stand-in for catacombs? The check gives they illuminate, so the matching form is illuminate. This gives a plural verb for the part describing the catacombs. Choice D.