使用must/mustn't描述规则 — 英语词汇题
题目
Tom 正在了解班级规则（class rules）。请根据中文提示和首字母补全单词，并选择 must 或 mustn't 填空，使句子正确。
1. You m______ (必须) listen to the teacher in class.
2. You m______n't run in the classroom. It's dangerous.
3. You must keep q______ (安静的) in the library.
4. You m______ (必须) keep your desk t______ (整洁的).