If Harry did not attend the conference last night, he too much work to do． [ ] A

If Harry did not attend the conference last night, he ________ too much work to do．

had to have had

had had

must have had

must have

试题答案

答案：C

注意条件句中的时态是did not attend，所以判断这不是叙述过去情况的虚拟语气。空格处是对过去情况的猜测——他一定昨天晚上有很多工作要做，所以才没有去参加会议的。