Question

【题目】— There's a sign "Be quiet" on the wall of the reading room.
— Yes. People ________ talk loudly in public.
A.may not
B.mustn't
C.couldn't
D.needn't

Answer 1

【答案】B
【解析】句意：-在阅览室的墙上有一个“安静”的标志。-是的。禁止人们大声说话。may not不可以;mustn't 禁止，不允许;couldn't不能;needn't不必。所以选B。