The historian explained that ancient civilizations _______ sophisticated irrigation systems long before the development of modern engineering.
6
readingWhich choice completes the text so that it conforms to the conventions of Standard English?
A
develop
B
have developed
C
are developing
D
had developed
Correct Answer: D
Choice D is the best answer. This question tests verb tense in past contexts.
- Context clues: The main verb "explained" is past tense; the action described happened even earlier.
- Meaning: Use past perfect for actions completed before another past action.
- Verify: "civilizations had developed... before the development" shows proper sequence.
💡 Strategy: Use past perfect (had + past participle) for an action completed before another past action.
Choice A is incorrect because present tense conflicts with past context. Choice B is incorrect because present perfect connects to present time. Choice C is incorrect because present progressive describes ongoing action now.