the fights ________because of the snowstrom,many passengers could do nothing but take the train.A.had been canceled B.have been cancled C.were canceled D.having been caneled 为什么选D

问题描述:

the fights ________because of the snowstrom,many passengers could do nothing but take the train.
A.had been canceled B.have been cancled C.were canceled D.having been caneled 为什么选D

因为这整个句子谓语动词是could do 前面的不是谓语,就用非谓语形式,非谓语形式有现在分词,过去分词,不定式,所以排除b c 又因为如果用had 就要是过去的过去,这句话没有具体的时间来对照,无法说明是过去的过去 ,所以选D

真正的主句是many passengers could do nothing but take the train.这是一个完整的句子.
中间用逗号隔开了,就表示the fights having been caneled because of the snowstrom不是一个句子,这里相当于一个状语从句.