—She looks very happy. She ________ have passed the exam.
—I guess so. It’s not difficult at all.
A. should B. could
C. must D. might
—She looks very happy. She ________ have passed the exam.
—I guess so. It’s not difficult at all.
A. should B. could
C. must D. might
【解析】选C。句意为：——她看上去很高兴，肯定通过这次考试了。——我猜也是，这次考试一点也不难。should have done表示“本应该做某事（而事实上并没有做）”；could have done用于肯定句时，表示“本可以做某事而未做”； must have done 表示对过去的肯定的推测；might have done表示对过去发生的动作不大肯定的推测，表示“可能/已经或许做了”。