句型：We must wait. 情态动词must — 英语填空题
题目
Su Hai 正要过马路（cross the road），此时红灯亮了。请根据交通规则，用情态动词 must 补全句子，每空一词：① The light is red. We ___ wait. ② We ___ not run across the road. ③ To cross the road safely, we ___ look at the traffic lights first.