问题补充:
------I don’t know why he has made such a silly mistake in the exam.
------ He it before he handed in the paper.
A. may have checked
B. might check
C. must have checked
D. should have checked
答案:
A. may have checked
B. might check
C. must have checked
(答案→)D. should have checked
解析: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。