Question

---I don’t know why he has made such a silly mistake in the exam.
--- He ______ it before he handed in the paper.

1. A.
   may have checked
2. B.
   might check
3. C.
   must have checked
4. D.
   should have checked

Answer 1

D
考查情态动词+have done的用法：A. may have checked可能已经检查了，B. might check 可能检查了， C. must have checked一定检查了，D. should have checked 本该检查而没有，句意是：--我不知道为什么他在考试中犯了这么愚蠢的错。--他本该交试卷钱检查一下的。选D。