––Whatajourney!We’vefinallyarrived!––_____anout-of-datetrainschedule,wew

––What a journey! We’ve finally arrived!––_____ an out-of-date train schedule, we would not have missed the train.A.Had we not usedB.Did we useC.If we didn’t useD.If we had used

A解析试题分析：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。考点：虚拟条件句的考查点评：注意区分真实条件句和虚拟条件句，真是条件句实现的可能性非常大，而虚拟条件句往往指不能实现的或纯属假想的情况。

就是这个解释