Bunuel
The massive Himalayan avalanche surprised climate scientists, who
saw a collapse that big and that fast – over 250 million cubic feet of snow and ice moving at speeds over 200 miles an hour – only once before.
(A) saw a collapse that big and that fast
(B) having seen a collapse that big and fast
(C) were seeing a collapse that big and fast
(D) will see a collapse that big and that fast
(E) had seen a collapse that big and that fast
https://www.nytimes.com/2018/01/23/climate/glacier-collapse-avalanche.htmlWhen 247 million cubic feet of snow and ice collapsed off a glacier in the dry, mountainous region of western Tibet in 2016, the roiling mass took with it nine human lives and hundreds of animals, spreading more than five miles in three minutes at speeds of nearly 200 miles per hour. The event surprised scientists, who
had seen a collapse that big and that fast only once before.
VERITAS PREP OFFICIAL SOLUTION:
This question is primarily testing tense and logical timelines. Whenever you have a choice of tense, you need to figure out which one conveys a logical timeline – if the timeline does not make sense you can eliminate that answer. This sentence begins with an event in the simple past tense: “the avalanche surprised climate scientists” and then you need to choose a logical tense for the verb “see”.
In (A) and (C), both tenses seem to create a logical timeline until you get to the end of the sentence, where it says “only once before” – because of this “saw” and “were seeing” make no sense, as they suggest that what they saw was when they were surprised by the avalanche, but it was actually something before.
Only (E) gets this correct by using the past perfect tense “had seen,” making it clear that this is referencing something before they were surprised by the avalanche. For (D), the future tense “will see” is clearly illogical in combination with “only once before” and in (B), the timeline is logical, but the second part of the sentence lacks an active verb: you cannot say “who having seen a collapse that big and fast only once before” - there would need to be some action at the end. The correct answer is (E).