We stopped talking when the teacher came in. 当老师进来时，我们停止说话。
(2)stop to do sth.(停下来去做某事)(指停下正在做的事，开始做另一件事) He stopped to have a rest.他停下来休息一下。 (3)stop sb. from doing sth. 阻止某人做某事
We must stop him from smoking.我们必须阻止他吸烟。 四、语法精讲 状语从句
1.由if引导的条件状语从句，if从句用一般现在时表将来。 We will go to the park if it doesn’t rain tomorrow. 如果明天天不下雨，我们就去公园。
If you jump the queue,other people will not be pleased. 如果你插队，别的人会不高兴。
2.由when,before,after引导的时间状语从句，如果主句是将来时态，从句用一般现在时表将来。
(1)I want to be a nurse when I grow up. 当我长大，想成为一名护士。
(2)When we see a red traffic light,we must be careful. 当我们看到红灯时，我们必须当心。
(3)They talked about the party after the people left. 人们离开之后，他们谈论这次聚会。
(4)We cleaned the lab before we left school yesterday. 我们昨天离开学校之前打扫了实验室。 ●发散迁移
大家对于本单元知识的掌握程度可以在下一环节中实验一下，看你能不能闯过三关。 ［一关四选一］
1.—Must I finish my homework this evening?
—No,you .You do it tomorrow. A.mustn’t;can B.needn’t;may C.can’t;may D.may;may
2.This book Lily’s.Look,her name is on the book cover. A.must be B.may be C.can’t be D.mustn’t be 3.He will go to the Great Wall if it tomorrow. A.won’t rain B.doesn’t rain C.don’t rain D.isn’t raining
4.Sorry,Miss Wang,I the key to the door of our classroom at home. A.left B.missed C.lost D.forgot ? A.can’t you B.mustn’t you C.needn’t you D.don’t you
6.Mary didn’t go to school yesterday she was ill in bed. A.when B.before C.because D.after 7.Yesterday we met interesting people in the History Museum.
