I set up email addresses for connecting with my parents last May. But I didn’t write to them as often as I ______. 
#62865
A
should
B
must have
C
should have
D
must
推荐题目
—Everyone in my class passed the exam.—Oh, really? It ________ difficult.
#62802
A
can’t have been
B
needn’t have been
C
must be
D
mightn’t be
People who drink wine ______ to drive after May Day. 
#77648
A
don’t allow
B
isn’t allowed
C
mustn’t allow
D
mustn’t be allowed