If you have something important to do you waste any time.A. needn’tB. mustn’tC. may notD

问题补充：

If you have something important to do, you waste any time.

A. needn’t

B. mustn’t

C. may not

D. won’t

答案：

A. needn’t

(答案→)B. mustn’t

C. may not

D. won’t

解析：根据句意应用mustn’t表示：不准。