题目内容：

________harder,you would have passed this exam.
A.If you have worked B.If you worked
C.Were you to work D.Had you worked

优质解答

D本题考查if虚拟语气中的用法.此题中有从句我已经通过了考试（would have passed ）,表明从句是过去时,故对过去进行虚拟全句话的意思就是我要是再努力一点,就通过考试了.由于此题中,主从句的主语都是一样的,故用Had ...