——Is John coming by train?——He should, but he ______ not.
A. must
B. can
C. need
D. may
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You have already tried your best, so you ______ worry about the matter.
A. can't
B. needn't
C. mustn't
D. couldn't
The fire spread through the building very quickly but everyone ______ get out.
A. had to
B. would
C. could
D. was able to
Please don't make so much noise. I ______ hear the speaker very well.
A. needn't
B. can't
C. shouldn't
D. mustn't
——Let's climb to the top of the tower.——You _____ be joking! I've been afraid of high places since I was a kid.
A. should
B. may
C. can
D. must