英语选择 求详解all the flights___because of the snow storm,many passengers could do nothing but take the train.A.had been cancelled B.were cancelledC.have been cancelled D.having been cancelled并列举相关知识点 别复制 要真心实意的答案 我想弄明白这个知识点
问题描述：
英语选择 求详解
all the flights___because of the snow storm,many passengers could do nothing but take the train.
A.had been cancelled B.were cancelled
C.have been cancelled D.having been cancelled
并列举相关知识点 别复制 要真心实意的答案 我想弄明白这个知识点
答