问题
选择题
He is an hour late by now.He last night.
A.must stay up
B.should stay up
C.should have stayed up
D.must have stayed up
答案
答案:D
考查情态动词表推测。根据last night,可知是指过去的事情,要用情态动词加完成时态,表对过去事实的推测,排除A,B;should have stayed up本应该熬夜而实际没有,must have stayed up表肯定熬夜了。根据他迟到这一事实,可知他昨晚肯定熬夜了,才导致迟到这一事实,所以选D。