By 1940, the pilot Jacqueline Cochran held seventeen official national and international speed records, and she earned them at a time when aviation was still so new for many of the planes she flew to be of dangerously experimental design.
(This question is from Official Guide. Therefore, because of copyrights, the complete question cannot be copied here. The question can be accessed at GMAT Club)
The sentence says:
The pilot JC had 17 official speed records by 1940. She earned these records at a time when aviation was so new that many of the planes she flew were dangerous to fly.
The sentence has one error: “aviation was still so new for many of the planes she flew” communicates that aviation was new for the planes!! Logically, it seems we want to use ‘so X that Y” idiom.
(A) Incorrect. For the reason mentioned above.
(B) Incorrect. For the following reasons:
- Repeats the meaning and idiomatic error of the original sentence.
- ‘for’, a preposition, is followed by a clause “many of the planes were…”. A preposition can never be followed by a clause.
(C) Incorrect. For the following reasons:
- ‘where’ refers to a place, not ‘time’. Therefore, its use is incorrect.
- The use of demonstrative pronoun ‘these’ without a noun following it is not recommended. The demonstrative pronouns ‘this’ and ‘these’ need to be followed by a noun e.g. this idea, these records etc.
(D) Incorrect. For the following reasons:
- The structure ‘so new such that’ is incorrect. It should be ‘so new that…”.
- Given the context of the sentence, the correct word for ‘time’ is ‘when’, not ‘in which’. (OG explanation says so and I agree)
(E) Correct. ‘earned’ acts as a verb-ed modifier correctly modifying ‘records’. Everything is fine with this option.