Question 3·Hard·Form, Structure, and Sense
Having examined satellite images and meteorological records spanning fifty years, _____ argue that the desert’s rapid expansion is due primarily to human activity rather than natural climate cycles.
Which choice completes the text so that it conforms to the conventions of Standard English?
For sentence-structure questions with an introductory phrase, first strip the sentence down to its core: identify the main subject and verb. Then check that the word or phrase directly after the comma logically matches the introductory modifier (it should be the one doing the action described in that opener) and that it agrees in number with the verb. Finally, prefer the option that is clear, logical, and concise, and avoid choices that make abstract things perform human actions or that create awkward, wordy constructions.
Hints
Locate the main verb
Find the main verb in the sentence and remember that the blank must be the subject of this verb.
Match the introductory phrase
Focus on the phrase before the comma: "Having examined satellite images and meteorological records spanning fifty years". Ask yourself: who or what could realistically do this examining?
Check for agreement
Look at the verb "argue". Is it singular or plural? Make sure the word or phrase you choose for the blank matches that number (singular/plural).
Eliminate illogical subjects
Eliminate any choice that makes something non-human (like an event or a conclusion) be the one that examined evidence and is now arguing a point.
Step-by-step Explanation
Identify the core sentence structure
Ignore the introductory phrase for a moment and find the main clause:
- Main verb: "argue"
- The blank must be the subject of this verb.
So the structure is: [subject] argue that the desert’s rapid expansion is due primarily to human activity…. Whatever goes in the blank is the thing (or people) doing the arguing.
Connect the introductory phrase to the subject
Now look at the beginning: "Having examined satellite images and meteorological records spanning fifty years, …"
This is a participial phrase. By standard English convention, it must logically describe the noun or noun phrase immediately after the comma (the subject in the blank).
So whoever goes in the blank must be someone who could examine images and records and then argue based on that examination. That strongly suggests a person or group of people, not an abstract idea or event.
Check subject–verb agreement
The verb is "argue", which is plural. So the subject in the blank must also be plural.
- A singular thing like a single event or a single conclusion would not match well with the plural verb "argue".
- We are looking for a plural noun phrase referring to people that can both examine data and argue about it.
Choose the option that is plural, logical, and concise
Now apply the tests:
- The subject must be able to examine data and argue a point (so it should refer to people).
- It must be plural to agree with "argue."
- It should fit smoothly and clearly after the comma.
Only "climatologists Diaz and Roe" works: "Having examined satellite images and meteorological records spanning fifty years, climatologists Diaz and Roe argue that the desert’s rapid expansion is due primarily to human activity rather than natural climate cycles." This is grammatical, logical, and concise, so "climatologists Diaz and Roe" (Choice B) is correct.