___harder,you could have have passed this exam.(B)

问题描述:

___harder,you could have have passed this exam.(B)
A.Were you worked B.Had you worked
C.if you worked D.If you have worked
请详解一下,同时翻译一下

B
=if you had worked
虚拟语气,had 提到前面要倒装
过去的事情假定,所以用虚拟语气