must / mustn't 的用法 — 英语选择题
题目
Tom is at the library. He sees a sign that says "Keep quiet" and another one that says "No eating or drinking". Which sentence uses must / mustn't correctly?
A. You must talk loudly here.
B. You mustn't keep quiet here.
C. You mustn't drink juice here.
D. You must eat snacks here.