Professor Li, many students want to see you. ______they wait here or outside?
A. Do
B. Shall
C. Did
D. Will
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We ______ them because of the noise from the river then .
A. could not have heard
B. must not hear
C. need not have heard
D. may not hear
The teacher told Jeremy, "You _____ an 'A' on your term paper, but you used toomany old expressions .
A. would have received
B. must have received
C. could receive
D. cannot have received
We had plenty of bread, so I _____a loaf.
A. mustn't have bought
B. didn't have to buy
C. needn't have bought
D. didn't need to buy
“ May I use your bike?”“No, you _______. ”
A. mustn't
B. needn't
C. may not
D. can't
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