情态动词must与mustn't — 英语填空题
题目
阅读图书馆规则卡，用 must 或 mustn't 填空（每空一词）。Library Rules Card: 1. You ___ be quiet in the library. 2. You ___ eat or drink here. 3. You ___ return(归还) the books on time. 4. You ___ draw pictures on the books. 5. You ___ keep the books clean.