Question 195·200 Super-Hard SAT Reading Questions·Standard English Conventions
Endorsements from respected scientists, along with a growing body of peer-reviewed studies, _____ the probiotic supplement's credibility, yet consumers should remain cautious about exaggerated marketing claims.
Which choice completes the text so that it conforms to the conventions of Standard English?
For subject-verb agreement questions, first strip the sentence down to its core by crossing out prepositional phrases (starting with words like "from," "of," "with") and add-on phrases like "along with" or "as well as" so you can clearly see the main subject. Decide whether that subject is singular or plural, then choose the verb form that matches it in number and fits the sentence’s time frame: general truths usually take simple present, while completed or ongoing-to-now actions might use perfect tenses. Eliminate any options that mismatch the subject’s number or create an unnecessarily awkward or specific tense for a general statement.
Hints
Find the real subject
Cover up the phrases "from respected scientists" and "along with a growing body of peer-reviewed studies" and see what the bare sentence looks like. What noun is left as the subject?
Ignore extra phrases for agreement
Remember that phrases starting with words like "from" or "along with" usually just add description and do not change whether the subject is singular or plural. Focus on the main noun when choosing the verb.
Check both number and tense
Once you know if the subject is singular or plural, make sure the verb form matches that number and fits the meaning: is the sentence describing a general, ongoing situation or a completed action?
Step-by-step Explanation
Locate the true subject of the sentence
Ignore the extra descriptive phrases and find the core subject:
- "Endorsements from respected scientists, along with a growing body of peer-reviewed studies, _____ the probiotic supplement's credibility"
The main noun doing the action is "Endorsements".
- "from respected scientists" is a prepositional phrase describing the endorsements.
- "along with a growing body of peer-reviewed studies" is another modifying phrase.
Neither of these phrases changes the subject; the subject is still plural: Endorsements.
Decide on the correct number and tense for the verb
Because the subject Endorsements is plural, the verb must also be plural.
Now consider tense and meaning:
- The sentence is making a general statement about how evidence supports the supplement right now and in general, not about a one-time action completed in the past.
- That kind of general, ongoing fact is usually expressed in the simple present tense (for example, "facts support," "studies show").
So we need a plural simple-present verb form that fits with a plural subject and a general truth.
Match the correct verb form to the subject and meaning
Check each answer against a plural simple-present requirement:
- bolsters – singular simple-present; would match a singular subject (like "The body bolsters"), not the plural "Endorsements."
- have bolstered – plural present perfect; suggests a completed or accumulated action rather than a general, ongoing fact.
- has bolstered – singular present perfect; wrong number and wrong tense for this sentence.
- bolster – plural simple-present; agrees with plural "Endorsements" and correctly expresses a general, ongoing support of the supplement's credibility.
Therefore, the correct answer is "bolster".