虚拟语气中的would/conld/should do/have done 与 did/had done有何区别

问题描述:

虚拟语气中的would/conld/should do/have done 与 did/had done有何区别

前面一部分是用在后面的主句里.后面一部分是用在if条件句里的.举个例子:If she had reviewed the text yesterday,she would have passed the exam.如果她昨天复习了课文,她是可以通过考试的.在例句中,had reviewed...