时间状语从句讲解与练习
【名师点睛】
用来修饰主句中的动词，副词和形容词的从句叫状语从句。根据其含义状语从句可分为时间状语从句，地点状语从句，条件状语从句， 原因状语从句，结果状语从句，比较状语从句，目的状语从句，让步状语从句。 1. 时间状语从句
(1)时间状语从句常用when, as, while, before, after, since, till, until, as soon as等连词来引导。例如： It was raining hard when got to school yesterday. While he was doing his homework, the telephone rang. As he walked along the lake, he sang happily.
He had learned a little Chinese before he came to China. After he finished middle school, he went to work in a factory.
(2)在时间状语从句里，通常不用将来时态，用现在时态表示将来的动作或状态。例如： I’ll ring you up as soon as I get to New York. I will tell him everything when he comes back. He won’t believe it until he sees it with his own eyes.
(3)在带有till或until引导的时间状语从句的主从复合句里，如果主句用肯定式，其含义是“一直到……时”，谓语动词只能用延续性动词。如果主句用否定式，其含义是“直到……才……”, “在……以前不……”, 谓语动词可用瞬间动词。例如： The young man read till the light went out. Let’s wait until the rain stops. We won’t start until Bob comes. Don’t get off until the bus stops.
2.when, while 和 as (“当„„时候”)的区别 一、when 的用法
如果从现象来看，when 从句用的最多的是一般过去时，而主句的时态没有,根据具体情况而定。 1. When he was a child he was always trying out new ideas. 他小时候就常常试验一些新的设想。 2. When she came into my room, I was just reading a book. 她走进我房间时，我正在看书。 3. Sorry, I was out when you called me. 对不起，你打电话来的时候我出去了。 4. I thought of it just when you opened your mouth. 就在你要说话的时候，我也想到了。
总结：when 从句的A事件，相当于另一个事件B发生的时间点。也就是说，when 从句的重点不在动作本身发生的状态，而只是把它作为一个时间点，所以when 多数情况下用的是一般过去时，则不用正在进行时。因为如果用正在进行时，它表示的就是一段时间而不是一个时间点了。根据这一点，有的文章补充说：when 从句的动词大多是瞬时动词。实际上，when 从句也可以有其它的时态，但几乎也不用进行时，因为它也只是作为一个时间参照点。例如：
1. When I got to the airport, the guests had left. 当我赶到飞机场时，客人们已经离开了。
2. When he had finished his homework, he took a short rest.当他完成作业后，他休息了一会儿。 3. You shall borrow the book when I have finished reading it. 在我读完这本书后，你可以借阅。 二、while 的用法
相比于when ，while 从句的侧重点在于描述动作正在发生的状态，它的意思是：当while 事件正在发生的时候，另一件事如何如何。所以，while 从句一般用的是正在进行时。而另一件事的状态没有硬性的要求，根据具体情况而定。例如：
1. While my wife was reading the newspaper, I was watching TV. 当妻子正在看报纸的时候，我正在看电视。
2. While Jim was mending his bike, Lin Tao came to see him. 正当吉姆修自行车时，林涛来看他。 3. While they were talking, the bell rang. 正在他们谈话的时候，上课铃响了。
从时间的角度来看，while 表示的是一段时间，是一个过程。因此，如果含有“一段时间”的含义的时候，就可以用while。
4. Strike while the iron is hot. 趁热打铁。
这句话中，是说趁着铁是热的这段时间，赶紧打铁。如果换成 when 意思就变了，相当于说铁只热了一下，打一下，然后铁就冷了。这显然不符合文意。
三、as 的用法
1） as 从句表示的也是一件事情正在发生，另一件事也正在进行当中。但与 while 从句不同的是，as 从句用的一般不用正在进行时，而只是一般过去时。as 从句一般可以翻译成“边„„边„„”。例如：
1. The students took notes as they listened. 学生们边听课边做笔记。
2. As we talked on, he got more and more excited. 我们继续往下谈的时候，他越来越兴奋。 3. The little girls sang as they went. 小姑娘们一边走，一边唱。 2）as 有“随着„„”，“随时间推移”之意。
1. As the time went on，the weather got worse. 随着时间的推移，气候更加糟糕。
2. As years go by，China is getting stronger and richer. 随着时间一年一年过去，中国变得越来越富强了。
少数情况下，如果强调动作正在发生，as 从句也可以用正在进行时。这只能算是特例了。 1. As we were going out, it began to snow. 正当我们出门时，雪开始下起来。 2. He came in as I was going to bed. 我正要上床睡觉，他进来了。
3.比较until和till
此两个连词意义相同。肯定形式表示的意思是“做某事直至某时”，动词必须是延续性的。否定形式表达的意思是“直至某时才做某事”。动词为延续性或非延续性都可以。正确使用这两个连词的关键之一就在于判断句中的动词该用肯定式还是否定式。 肯定句：I slept until midnight. 我一直睡到半夜时醒了。
Wait till I call you. 等着我叫你。
否定句：She didn't arrive until 6 o'clock. 她直到6点才到。
Don't get off the bus until it has stopped. 公共汽车停稳后再下车。 区别：1）until可用于句首，而till通常不用于句首。 例如：Until you told me, I had heard nothing of what happened.
直到你告诉我以前，出了什么事我一点也不知道。
2）Not until„在句首，主句用倒装。
例如：Not until the early years of the 19th century did man know what heat is. 直到19 世纪初，人类才知道热为何物。
Not until I began to work did I realize how much time I had wasted. 直到工作，才认识到我已蹉跎了许多岁月。 4.表示“一„„就„„”的结构
no sooner„than 和as soon as都可以表示“一„„就„„”的 意思。例如： I had no sooner got home than it began to rain. As soon as I got home, it began to rain.
练习：在下列各句的空格中填入适当的连词 1. I was about to go out _________ a visitor came. 2. He learned to speak German _________ he was in Berlin. 3. Henry is in charge of the office ________ Mr. Smith is away. 4. I listen to the recorder _________ I have time. 5. He had learned Chinese _________ he came to China.
6. _________ the work was done, we sat down to sum up experience. 7. It was not ________ he took off his eyeglasses that I recognized him. 8. The thieves ran away _________ they caught sight of the police. 9. They decided to go back home _________ their money ran out. 10. __________ I get to the airport, I will phone you to pick me up. 11. They were about to leave ______ it began to rain. 12. He always stay in bed ______ lunch time.
13. I like playing tennis _________ my younger sister prefers watching ball games. 14. _________ I understand your viewpoint, I don’t agree with you. 15. _______ she grew older, she became more responsible.
