Had they known what was ing next, they ___________ second thoughts.
A.may have
B.could have
C.must have had
D.might have had
网友回答
D解析本题考查虚拟语气的用法。本句是一个倒装句，可还原为：if they had known what was ing next, they might have had second thought。根据had known提示，可知是与过去事实相反，因此虚拟语气主句中应该用would/might have done，由此可见