( )1.(2012年福建南平)—I can't stop smoking, doctor.
—For your health, I'm afraid you ________.
A.must B.can
C.may
( )2.(2012年福建南平)Don't ________ too late, or you'll feel tired tomorrow.
A.wake up B.put up
C.stay up
( )3.(2012年黑龙江大庆)—May we leave the classroom now?
—No, you________.You________ to leave until the bell rings.
A.mustn't; are allowed
B.don't have to; are supposed
C.needn't; aren't allowed
D.can't; aren't supposed
