掌门1对1教育高中英语时间、原因、条件状语从句一．when, while 和as 引导时间状语从句的区别用法（一）when 的用法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。
（口头练习）When I got to the airport, the guests had left.Why do you want a new job when you have got such a good one already?(二)while 的用法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。
而另一件事的状态根据具体情况而定。
（口头练习）1. While my wife was reading the newspaper, I was watching TV.2. While Jim was mending his bike, Lin Tao came to see him.从时间的角度来看，while 表示的是一段时间，是一个过程。
趁热打铁。
Strike while the iron is hot.（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。
as 从句用的一般不用正在进行时，而只是一般过去时。
可以翻译成“边……边……”。
（口头练习）As my mother sang those old songs, tears ran down her cheeks.The students took notes as they listened.as 表达的事件，往往只是主句动作发生的背景或条件时，as 只是一个次要的时间说明，常常翻译成“随着……”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. The atmosphere gets thinner and thinner as the height increases. 随着高度的增加，大气越来越稀薄。
（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。
The sad mother sat on the roadside, shouting as she was crying. 伤心的妈妈坐在路边，边哭边叫喊。
）总结：1）as, when 引导短暂性动作的动词。
2）当从句的动作发生于主句动作之前，只能用when 引导这个从句3）从句表示“随时间推移”连词能用asExercise：1.the day went on, the weather got worse.2. Just I stopped my car, a man came up to me.3.the manager comes here for a visit next week, I’ll talk with him about this.4. —I'm going to the post office.— you're there, can you get me some stamps?Key: As When/as When While二.until和till 的用法区别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。
肯定句：I slept until midnight.Wait till I call you.否定句：She didn't arrive until 6 o'clock.Don't get off the bus until it has stopped. 公共汽车停稳后再下车。
I didn't manage to do it until you had explained how. 直到你教我后，我才会做。
区别：until可用于句首，而till通常不用于句首；表示“直到…才”用untilUntil you told me, I had heard nothing of what happened.Not until…在句首，主句用倒装。
Man didn’t know what heat is until the early years of the 19th century.Not until the early years of the 19th century did man know what heat is.I didn’t realize how much time I had wasted until I began to worl.Not until I began to work did I realize how much time I had wasted.三.表示“一……就……”的结构1.as soon as, once, directly, immediately, instantly, the moment, the instant,the minute2. hardly/scarcely…when/before, no sooner…than(主句常用过完)As soon as I got home, it began to rain.=I had hardly / scarcely got home when it began to rain.=I had no sooner got home than it began to rain.注意：如果hardly, scarcely 或no sooner置于句首，句子必须用倒装结构。
Hardly / Scarcely had I got home when it began to rain.No sooner had I got home than it began to rain.3.Instantly, immediately, directlyI got up to open the door immediately the bell rang.4.The moment, the instant, the minuteWe thrilled with joy the very minute we set foot on the soil of our motherland.Exercise:Fill in the blanks with proper words.1．_________ he comes tomorrow, I shall ask where he has been.2．_________ he was speaking, everybody listened carefully.3．I saw her just _________ she was getting off the train.4．Have a good look at that man _________ you pass him.5．It was already eight o'clock _________ we got there.6. I was about to go out _________ a visitor came.7．We'll go to the country at the beginning of June, ______ the summer harvest will start.8. He learned to speak German _________ he was in Berlin.9. Henry is in charge of the office ________ Mr. Smith is away.10. I listen to the recorder _________ I have time.11. He had learned Chinese _________ he came to China.12. _________ the work was done, we sat down to sum up experience.13. I haven't seen him _________ he moved to the other side of the town.14. I waited ________ he came back.15. It was not ________ he took off his eyeglasses that I recognized him.16. She likes everything to be in place ________ she starts to work.17. The thieves ran away _________ they caught sight of the police.18. They decided to go back home _________ their money ran out.19. We played outside till sunset, _________ it began to rain。
20. __________ I get to the airport, I will phone you to pick me up.21. They were about to leave ______ it began to rain.22. He always stay in bed ______ lunch time.23. I like playing tennis _________ my younger sister prefers watching ball games.24. _________ I understand your viewpoint, I don’t agree with you.25. _______ she grew older , she became more responsible.Key: 1. When 2. While / When 3. as 4. when/as 5. when 6. when7. when 8. while 9. while 10. whenever 11. before 12. After 13. since 14. till/until 15. until 16. before 17. as soon as 18. before 19. when20. As soon as 21.when 22. until 23. while 24. While 25. As1.Because he was ill, he didn't go to school 。
