【答案】We all should obey the rules. You ____talk loudly or smoke in the library.

We all should obey the rules. You ____talk loudly or smoke in the library.

A. don't have to B. mustn't C. can't D. shouldn’t

【答案】

B

【解析】

句意：我们都应该遵守规则。你不能在图书馆里大声讨论或者抽烟。考查情态动词用法。A表示不必，没必要。B表示不许(语气最强)。C表示不能，D表示不应该。根据句意，故选B。