情态动词must/should谈规则 — 英语词汇题
题目
用 must, mustn't 或 should 填空（每词限用一次）。(1) Traffic rules are serious: You ___ stop and wait when the light is red. (2) You ___ swim in this river; the water runs too fast and it's dangerous. (3) You look very tired, so you ___ go to bed early tonight.