情态动词表建议与义务 — 英语选择题
题目
在学校图书馆里，保持安静是规定，而轻声讨论只是管理员给出的建议。下列哪句话准确表达了这两层意思？ A. You should keep quiet, and you may not discuss. B. You must keep quiet, but you needn't discuss. C. You must keep quiet, and you'd better discuss in a low voice. D. You needn't keep quiet, but you must discuss loudly.