All flights _________ because of the snowstorm,many passengers could do nothing but take the train.
题目
All flights _________ because of the snowstorm,many passengers could do nothing but take the train.
A.had been canceled
B.have been canceled
C.were canceled
D.having been canceled
答案
因为句中逗号,逗号前不是一个句子,所以直接排除ABC,选D
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