Question 96·Hard·Form, Structure, and Sense
Geologists recently published a comprehensive assessment of Country X's mineral reserves. The abundance of rare earth minerals discovered in the region, as well as the researchers who documented them, ______ prompted the government to revise its export regulations.
Which choice completes the text so that it conforms to the conventions of Standard English?
For subject–verb agreement questions, first cross out prepositional phrases ("of ...") and any phrases set off by commas (especially ones starting with words like "as well as" or "along with") so you can clearly see the core subject. Decide whether that subject is singular or plural, then choose the verb form that matches its number and creates a natural, standard verb phrase in context. Quickly read the sentence with your chosen verb to check that the tense and structure sound complete and logical.
Hints
Locate the main subject
Ignore the descriptive phrases (such as "of rare earth minerals discovered in the region") and the part in commas. What is the one main thing that actually "prompted the government"?
Think about "as well as"
Treat the phrase "as well as the researchers who documented them" like extra information similar to "in addition to the researchers." Does that part usually change whether the verb is singular or plural?
Match subject and verb form
Once you know if the subject is singular or plural, choose the helping verb that both matches that number and forms a natural, standard verb phrase before "prompted." Pay attention to whether any choices create awkward or ungrammatical combinations.
Step-by-step Explanation
Identify what the blank is doing
The blank comes right before "prompted," so it must be a helping verb that completes the verb phrase.
You want a verb phrase that describes what caused the government to revise its export regulations: something "___ prompted the government to revise its export regulations."
Find the core subject of the sentence
Strip away extra details to find the main subject. Start with this part:
- "The abundance of rare earth minerals discovered in the region, as well as the researchers who documented them, ___ prompted the government..."
First, ignore the prepositional phrase "of rare earth minerals discovered in the region." That leaves:
- "The abundance ..., as well as the researchers who documented them, ___ prompted..."
The phrase "as well as the researchers who documented them" is set off by commas and works like extra information (similar to "in addition to the researchers"). The core subject is "The abundance", which is singular.
Decide what kind of verb form is needed
Because the subject "abundance" is singular, the helping verb must also be singular.
Also, the sentence describes a recent action with present relevance (recent publication leading to a change now), so a present-perfect form like "has prompted" or "have prompted" is appropriate. For a singular subject, we use "has"; for a plural subject, we would use "have."
Test each answer choice with the subject
Now plug each option in with the subject "The abundance ...":
- "The abundance ..., as well as the researchers who documented them, have prompted..." → uses a plural verb with a singular subject → incorrect.
- "The abundance ..., as well as the researchers who documented them, were having prompted..." → ungrammatical verb phrase; "were having prompted" is not standard English.
- "The abundance ..., as well as the researchers who documented them, are having prompted..." → also ungrammatical; "are having prompted" does not make sense.
- "The abundance ..., as well as the researchers who documented them, has prompted..." → singular subject with singular helping verb and a correct, natural present-perfect verb phrase.
Therefore, the correct choice is D) has.