【题目】If William had listened to what his teacher said in class, he how to solve the problem now.
A.has knownB.would knowC.would have knownD.knows
在线课程【答案】B
【解析】
考查虚拟语气。句意：如果William听了他老师在课上说的，他现在就知道如何解决这个问题了。本题为错综时间条件句中的虚拟语气，即条件从句与主句所指时间不一致，如从句指过去，而主句即指的是现在或将来。本句中从句表示对过去情况的假设，而主语中根据now可知表示对现在情况的假设，谓语动词用would+动词原形，故选B。