Question 30·200 Super-Hard SAT Reading Questions·Standard English Conventions
Because the electrons in the alloy’s outer shell were thought to be only weakly bound, researchers _____ that the material would make an excellent conductor, but later experiments revealed that it was, in fact, an insulator.
Which choice completes the text so that it conforms to the conventions of Standard English?
For verb tense questions, first underline all the main verbs in the sentence and note their tenses, then look for time clues like "later," "by then," or specific dates to establish a timeline. If two actions happened in the past and one clearly occurred before the other, use simple past for the later action and past perfect ("had" + past participle) for the earlier one. Eliminate choices that shift the time frame to the present (like present perfect) or that introduce an unnecessary progressive form when no ongoing, interrupted action is described.
Hints
Notice the time word
Pay close attention to the word "later" before "experiments revealed." How does that affect the timing of the action in the blank?
Compare when each action happened
Ask yourself: Did the researchers form their belief before, at the same time as, or after the experiments? Which tense would best show that order?
Match the overall time frame
Both "were thought" and "revealed" are in the past. Which answer choice uses a verb tense that fits this past time frame and shows that the assumption came earlier than the experiments?
Step-by-step Explanation
Locate the time clues in the sentence
Read the full sentence and notice the time words and verb tenses:
- "were thought" — simple past
- "later experiments revealed" — simple past with the time clue "later"
The word "later" tells you that the experiments happened after the earlier thinking and assuming.
Figure out the order of past events
There are three key actions:
- Electrons were thought to be weakly bound.
- Because of that, researchers [blank] that the material would be a good conductor.
- Later experiments revealed that it was actually an insulator.
Events 1 and 2 happen first; event 3 (the experiments) happens later. The blank must describe an action that was already completed before the "later experiments revealed" part.
Recall which tense shows an earlier past event
When you describe two past events and need to show that one happened before the other, you usually:
- Use simple past for the later event (here: "experiments revealed"), and
- Use past perfect ("had" + past participle) for the earlier event.
So we want the choice that puts the researchers’ assumption in the past perfect relative to "later experiments revealed."
Check each choice for tense and fit, then select the best one
Now evaluate the options:
- have assumed — present perfect (connects past to present) → does not match the fully past time frame.
- assumed — simple past; does not clearly show that this action was completed before the "later" experiments.
- were assuming — past progressive; suggests an ongoing action, which does not fit the idea of a settled belief.
- had assumed — past perfect; clearly marks the assumption as occurring before the later experiments.
Therefore, the correct answer is “had assumed.”