1 . We _______ have bought so much food now that Suzie won’t be with us.

A．may not

B．can’t

C．mustn’t

D．needn’t

2 . The boss ______ the worker how to do it, or the accident couldn’t have happened.

A．can’t have told

B．ought to tell

C．could have told

D．mustn’t have told

3 . —What did you say to your sister? I saw her crying in the room.
— It _________ my fault. I just said hello to her when I met her, nothing else.

A．must have been	B．can’t have been
C．oughtn’t to be	D．should have been