Question 68·Medium·Form, Structure, and Sense
According to the park’s wildlife biologist, the population of river otters has increased by nearly 40 percent over the past decade, a trend that _____ the success of the habitat restoration project.
Which choice completes the text so that it conforms to the conventions of Standard English?
For subject–verb agreement questions inside relative clauses (starting with words like "that," "which," or "who"), first strip the sentence down to the key noun and verb (for example, "trend ___"). Identify whether that noun is singular or plural, then choose the verb form that matches it, ignoring any words or phrases that come between the noun and the verb. Quickly eliminate forms that create fragments (like participles without helping verbs) or that use the wrong number (singular vs. plural).
Hints
Find what the word in the blank is doing
Look at the phrase "a trend that _____ the success." Ask yourself: what part of speech is missing here? Is it supposed to be a main verb or something else?
Identify the subject for agreement
In the phrase "a trend that _____," what is the noun that "that" refers back to? Is it singular or plural?
Check the verb form carefully
For a singular subject in the present tense, what ending do regular verbs usually take? Eliminate any choices that do not agree in number with that subject or that turn the clause into a fragment.
Step-by-step Explanation
Locate the clause that needs a verb
Focus on the part of the sentence with the blank: "a trend that _____ the success of the habitat restoration project."
This is a relative clause starting with "that" and modifying the noun "trend." The word in the blank must function as the main verb of this clause.
Identify the subject of the verb
In the clause "that _____ the success," the subject is the word right before "that" that the clause refers to.
Here, that word is "trend" in the phrase "a trend that ___." So the subject of the verb in the blank is "trend," which is singular.
Match the verb form to the singular subject
Because the subject "trend" is singular, the verb in the present tense must also be singular. In Standard English, singular present-tense verbs for most verbs end with -s (for example, "the trend shows," "the data suggests").
Among the options, only "demonstrates" is a singular present-tense verb that correctly completes the clause: "a trend that demonstrates the success of the habitat restoration project." This is the correct answer.