Question

这道英语题选啥？

If he ___ to the teacher attentively, he ___ the answer to the problem now.

A. had listened, would have known B. listened, would know

C. listened, would have known D. had listened, would know

Answer 1

If he ___ to the teacher attentively, he ___ the answer to the problem now
D. had listened, would know
解答：这道题目是考查虚拟语气中的交叉虚拟问题。
即，当虚拟条件句中，主句和从句的时间是不一致的时候，应分别考虑不同时间下的虚拟状况。
按照本句的实际情况，listen发生的时间应在过去，那么对于过去时间的虚拟采用过去完成时，had listened ;而know the answer 发生在现在，那么对现在时间的虚拟采用would +动词原形，也就是would know

Answer 2

D

表示假如过去他认真听老师讲课，那么现在他就应该知道问题的答案。
实际是：1、过去他没有认真听 2、现在他也不知道答案。
所以前后都用虚拟语态，前面是过去式的虚拟语态，用过去完成时，后面是现在的虚拟语态，用过去时

Answer 3

D
虚拟语气，所有时态都要往后推一次

Answer 4

选D

Answer 5

B 虚拟语气错综条件句

Answer 6

楼上的，你们都是胡说
这道题应该选A，不错，这句话是虚拟语气。此句应该是对过去情况虚拟，主句用would have done，从句用过去完成时。