问题

Everyone passed the exam.It _________ difficult.
A:can’t have been
B:must have been
C:couldn’t be
D:might have been
B:must have been
C:couldn’t be
D:might have been
正确答案是:
同类题型
Weareallgoingtothegames.Whydon’tyoucome________?
Hi, Jane! Can you go hiking with me on Sunday— . I have too much homework.
You ________ more careful next time.
Are you fond of watching TV?— Not a bitI would sit alone in the dark _______ I would watch TV
All flights ____ because of the snowstorm, many passengers could do nothing but take the train