—Another cup of coffee?
—No, thanks. I _____ be off. Mary is waiting for me.
A．can B．may
C．must D．might
You _______ smoke in the hospital.
A．needn’t B．oughtn’t to
C．ought to not D．may not
You’d better _____late again.
A．don‘t B．not be
C．not being D．won’t be
You_____ to the meeting this afternoon if you have something important to do.
A．needn’t to come B．don’t need come
C．don’t need coming D．needn’t come
To make our city more beautiful, rubbish ______ into the river.
A．needn't be thrown B．mustn't be thrown
C．can't throw D．mustn’t throw
—Who is the man over there? Is it Mr Li?
—No, it ______ be him. Mr Li has gone to America.
A．mustn't B．may not
C．can't D．needn't
