--- How much shall I pay for the phone call? --- You ________. This is free of charge. 
#87096
A
shouldn’t
B
can’t
C
don’t have to
D
mustn’t
推荐题目
He ____ have the ticket if I buy it . 
#89762
A
will
B
must
C
shall
D
ought、
I ________ you how to deal with the matter, but why didn’t you ask me?
#86841
A
could show
B
were to show
C
had shown
D
would have shown