All flights because of the snowstorm we decided to take the train instead.A. were canceled

问题补充：

All flights because of the snowstorm，we decided to take the train instead.

A. were canceled

B. had been canceled

C. having canceled

D. having been canceled

答案：

A. were canceled

B. had been canceled

C. having canceled

(答案→)D. having been canceled

解析：本题考查独立主格结构。根据句子结构，空格应填非非谓语动词，排除AB，其逻辑主语为All flights，而句子的主语是we，因此是考查独立主格结构，flights与cancel之间为被动关系，故选Ｄ。若选Ｂ，则题目应变成when引导的时间状语从句