––What a journey! We’ve finally arrived!
–– an out-of-date train schedule, we would not have missed the train.
A. Had we not used
B. Did we use
C. If we didn’t use
D. If we had used
网友回答
(答案→)A. Had we not used
B. Did we use
C. If we didn’t use
D. If we had used
解析：通过分析句子，可知其中包含一个虚拟条件句。根据主句“we would not have missed the train”可看出这是对过去情况的虚拟，所以条件句用过去完成时。又因为虚拟条件句中有had, should, were时，可以将if去掉，然后把had, should, were提到主语前面，故选A。