An agreement question tests whether a verb matches its subject: one thing takes a singular verb; several take a plural verb. Sort the forms by number, then check for a main verb saying what the subject does or is. An -ing form needs a helper to be a main verb. Ask who or what the verb is about, then cross out describing phrases. Test with it or they, because the subject decides the verb, not the nearest noun.
Hints
- Hint 1
Look at the part after the comma. Does it already have a main verb saying what its subject does or is?
- Hint 2
Cross out the phrase beginning with carved, then test the subject with it or they.
Step-by-step
Find the true subject
Step 1Check for a main verb
Sort the forms by number: remains and has remained are singular, while remaining can't be a main verb on its own. Does the blank need a main verb saying what its subject does or is? In Although the ancient sculpture's surface appears weathered, appears belongs to the opening part. The phrase carved along its base only describes the patterns, so the words after the comma still need a main verb.
- Step 2
Find what's still sharp
What is still remarkably sharp? It's the intricate patterns, so let's cross out the carving phrase to bring that subject beside the blank. The base tells where the patterns were carved, and the sculpture's surface belongs to the opening part, so neither decides this verb's number. The patterns are plural, which means we need a verb for more than one.
- Step 3
Match the verb to the subject
Replace the intricate patterns with they: they remain is the plural form. Remain is the main verb that matches the subject, so it completes the sentence. Choice D.