题目内容：

[10] All flights _____ because of the snowstorm,we decided to take the train
.
A.were canceled
B.had been canceled
C.have canceled
D.having been canceled
翻译包括选项,详细分析句子.

优质解答

答案D你的句子是独立主格结构句子.如果变成非独立主格结构句子就成了：As / Since all flights had been cancelledbecause of the snowstorm,we decided to take the train.这样的从句必须有连接词as / since.如果没...