If you go into a store and feel that the clerk is being rude, stop and think that she____ a tough day, and put yourself in her shoes. 
#88069
A
may have
B
may have had
C
must have
D
should have had
推荐题目
I ______ Peter with his work, but I had a lot of things to do myself.
#86588
A
must have helped
B
should have helped
C
needn’t have helped
D
can’t have helped
We _____ a pleasant journey but for the rain.
#90446
A
would have
B
will have
C
had had
D
would have had
Look at the trouble I am in. If only I _____ your advice.
#87134
A
followed 
B
would follow
C
had followed 
D
should follow