Unit 8 Natural disasters------when while as 辨析课件
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| 名称 | Unit 8 Natural disasters------when while as 辨析课件 |  | |
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| 文件大小 | 93.1KB | ||
| 资源类型 | 教案 | ||
| 版本资源 | 牛津译林版 | ||
| 科目 | 英语 | ||
| 更新时间 | 2017-08-29 13:07:57 | ||
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课件18张PPT。when, while, as 引导时间状语从句的区别 这三个词的意思很简单，都有“当……时候”的意思。但学生经常会问三个词的区别在哪儿，特别是在做选择题的时候。别说是学生，就我个人而言，做这样的选择题要保证百分之百的正确也是不可能的。一、when 的用法 when表示“当……的时候”，从句中既可用延续性动词，又可用非延续性动词；这些动词既可以表示动作，又可表示状态；从句中的动作既可和主句的动作同时发生，又可在主句的动作之前或之后发生。从句用一般过去时较多。
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。(主句动作之后)(短暂性动词)
when she came into my room? I was just reading a book.
她走进我房间时，我正在看书。(同时发生)(短暂性动词)
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。 (主句动作之前)(短暂性动词)
Sorry, I was out when you called me.?
对不起，你打电话来的时候我出去了。(同时发生)(延续性动词)二、while 的用法 while表示“在……的时候”、“在……期间”。它强调主句的动作与从句的动作同时发生或主句的动作发生在从句的动作过程中。while引导的从句中必须是表示动作或状态的延续性动词。while 从句一般用的是进行时。 而另一件事的状态没有硬性的要求。从句常用进行时。
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。(延续性动词)
While they were talking , the bell rang.
正在他们谈话的时候，上课铃响了。(延续性动词)
You can't do your homework while you are watching TV.
你不能一边看电视一边做家庭作业。(延续性动词)
Strike while the iron is hot. 趁热打铁。(延续性动词)
三、as 的用法as从句中既可用延续性动词，又可用非延续性动词；它强调主句的动作与从句的动作同时发生。as的用法比较复杂，具体如下：
1、表示“当……时；和……同时”。从句中多用表示动作的动词，而不用be动词或表示感觉、理解、知道这类动词。此时as的用法与while和when相近。例如：
As he stood there, he saw two men enter the old house.
当他站在那儿时，他看到两个男人进了那个老房子。(延续性动词)
As I was walking down the street, an American asked me for directions to the nearest station.
当我走在街上时，一位美国人向我询问到最近的车站的路线。(延续性动词)2、as用于平行的动作中，常指一个主语同时进行两个动作。但与 while 从句不同的是，as 从句用的一般不用进行时，而只是一般过去时。as 从句一般可以翻译成“边……边……”。例如：
The students took notes as they listened．
学生们边听课边做笔记。(短暂性动词)
The little girls sang as they went．
小姑娘们一边走，一边唱。(短暂性动词)
Just as he caught the ball, there was a tearing sound. 当他抓住球的时候,有一种撕裂的声音。 (短暂性动词)3、用于平行发展的结构中。常指一个行为是另一个行为的结果，或一种状态随另一种状态变化。句中的动词多表示状态的发展变化。此时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，不像while 从句有强调 while 动作本身的意思。因此，as 常常翻译成“随着……”之意。 例如：The atmosphere gets thinner and thinner as the height increases.
随着高度的增加，大气越来越稀薄。
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。
As he grew older he became more confident.
随着他的长大，他越来越自信。
???? 四、when, while, as 的互换 ??? 如果从句动作和主句动作同时发生，并且从句动作为延续性动词时，when，while，as 可以互换使用。这种情况下，它们的细微区别恐怕连英、美人自己也说不清了。
When /While /As we were dancing，a stranger came in.
当我们跳舞时，一位陌生人走了进来。
When /While /As she was making a phonecall，I was writing a letter.
当她在打电话时，我正在写信。
While/When/ As I was walking down the street, I noticed a police car in front of the bank.
我顺着马路往前走时,发现银行门前停着一辆警车。when, as, while 总结1、When可指时间点，又可指时间段，从句中可用延续性动词，也可用非延续性动词。
2、While总是指一个时间段，从句中必须用延续性动词。
3、as多用于平行结构。表示两个动作同时发生；一个主语同时进行两个动作；一种状态随另一种状态的变化而变化。
4、主句的动作和从句动作同时发生，并且从句是延续性动词，when, while, as均可使用。从句中为be动词时，多用when和while。谈论两个同时进行的长动作可用while，谈论两个平行动作或两种状态变化多用as。综合练习( )1、I _______my homework while Dad _________Beijing Opera last night.
A. did; have enjoyed B. was doing; was enjoying
C. had done; was enjoying D. would do; was enjoying
( )2、_______ he walked, he talked.
A. When B. While C. As D. So
( )3、—I'm going to the post office.
—_____ you are there, can you buy me some stamps?
A. As B. While C. Because D. If
( )4、He was just leaving ________ the telephone rang．
A．while B．when C．as D．until
( )5、In China and some other countries, it is impolite to speak loudly _________ you are having a meal.
A. before B.while C. after D. as
( )6、Babies sleep 16 to 18 hours in every 24 hours, and they sleep less ________ they grow older.
A. while B. as C. when D. after
( )7、He was about to go to bed __________ the door bell rang.
A. as B. when C. while D. and
( )8、John was studying in his room __________ he heard screaming.
A. when B. while C. as D. then 二、用when, while, as 填空。
_________________ I was walking down the street, I noticed a police car in front of the store. （同时发生）
2) _________ John arrived, I was cooking lunch.
3) ______ he grew older, he lost interested in everything except gardening.
4) I was wandering through the street _________I caught sight of a tailor’s shop.While/When/AswhenAswhen5)He was copying a text ___________ his brother came in.
6) Mary learnt a lot _________ she was only 7.
7) _______________ I was drinking, father came in.
8) They bought many food ________________ Mike was studying.
9) ___________________ the thief was stealing the DVD, a lot of people came in.
10) __________he fell down, he came up with an idea.
whenwhenWhile/whenwhile/whenWhile/whenWhen
Thank you!
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。(主句动作之后)(短暂性动词)
when she came into my room? I was just reading a book.
她走进我房间时，我正在看书。(同时发生)(短暂性动词)
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。 (主句动作之前)(短暂性动词)
Sorry, I was out when you called me.?
对不起，你打电话来的时候我出去了。(同时发生)(延续性动词)二、while 的用法 while表示“在……的时候”、“在……期间”。它强调主句的动作与从句的动作同时发生或主句的动作发生在从句的动作过程中。while引导的从句中必须是表示动作或状态的延续性动词。while 从句一般用的是进行时。 而另一件事的状态没有硬性的要求。从句常用进行时。
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。(延续性动词)
While they were talking , the bell rang.
正在他们谈话的时候，上课铃响了。(延续性动词)
You can't do your homework while you are watching TV.
你不能一边看电视一边做家庭作业。(延续性动词)
Strike while the iron is hot. 趁热打铁。(延续性动词)
三、as 的用法as从句中既可用延续性动词，又可用非延续性动词；它强调主句的动作与从句的动作同时发生。as的用法比较复杂，具体如下：
1、表示“当……时；和……同时”。从句中多用表示动作的动词，而不用be动词或表示感觉、理解、知道这类动词。此时as的用法与while和when相近。例如：
As he stood there, he saw two men enter the old house.
当他站在那儿时，他看到两个男人进了那个老房子。(延续性动词)
As I was walking down the street, an American asked me for directions to the nearest station.
当我走在街上时，一位美国人向我询问到最近的车站的路线。(延续性动词)2、as用于平行的动作中，常指一个主语同时进行两个动作。但与 while 从句不同的是，as 从句用的一般不用进行时，而只是一般过去时。as 从句一般可以翻译成“边……边……”。例如：
The students took notes as they listened．
学生们边听课边做笔记。(短暂性动词)
The little girls sang as they went．
小姑娘们一边走，一边唱。(短暂性动词)
Just as he caught the ball, there was a tearing sound. 当他抓住球的时候,有一种撕裂的声音。 (短暂性动词)3、用于平行发展的结构中。常指一个行为是另一个行为的结果，或一种状态随另一种状态变化。句中的动词多表示状态的发展变化。此时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，不像while 从句有强调 while 动作本身的意思。因此，as 常常翻译成“随着……”之意。 例如：The atmosphere gets thinner and thinner as the height increases.
随着高度的增加，大气越来越稀薄。
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。
As he grew older he became more confident.
随着他的长大，他越来越自信。
???? 四、when, while, as 的互换 ??? 如果从句动作和主句动作同时发生，并且从句动作为延续性动词时，when，while，as 可以互换使用。这种情况下，它们的细微区别恐怕连英、美人自己也说不清了。
When /While /As we were dancing，a stranger came in.
当我们跳舞时，一位陌生人走了进来。
When /While /As she was making a phonecall，I was writing a letter.
当她在打电话时，我正在写信。
While/When/ As I was walking down the street, I noticed a police car in front of the bank.
我顺着马路往前走时,发现银行门前停着一辆警车。when, as, while 总结1、When可指时间点，又可指时间段，从句中可用延续性动词，也可用非延续性动词。
2、While总是指一个时间段，从句中必须用延续性动词。
3、as多用于平行结构。表示两个动作同时发生；一个主语同时进行两个动作；一种状态随另一种状态的变化而变化。
4、主句的动作和从句动作同时发生，并且从句是延续性动词，when, while, as均可使用。从句中为be动词时，多用when和while。谈论两个同时进行的长动作可用while，谈论两个平行动作或两种状态变化多用as。综合练习( )1、I _______my homework while Dad _________Beijing Opera last night.
A. did; have enjoyed B. was doing; was enjoying
C. had done; was enjoying D. would do; was enjoying
( )2、_______ he walked, he talked.
A. When B. While C. As D. So
( )3、—I'm going to the post office.
—_____ you are there, can you buy me some stamps?
A. As B. While C. Because D. If
( )4、He was just leaving ________ the telephone rang．
A．while B．when C．as D．until
( )5、In China and some other countries, it is impolite to speak loudly _________ you are having a meal.
A. before B.while C. after D. as
( )6、Babies sleep 16 to 18 hours in every 24 hours, and they sleep less ________ they grow older.
A. while B. as C. when D. after
( )7、He was about to go to bed __________ the door bell rang.
A. as B. when C. while D. and
( )8、John was studying in his room __________ he heard screaming.
A. when B. while C. as D. then 二、用when, while, as 填空。
_________________ I was walking down the street, I noticed a police car in front of the store. （同时发生）
2) _________ John arrived, I was cooking lunch.
3) ______ he grew older, he lost interested in everything except gardening.
4) I was wandering through the street _________I caught sight of a tailor’s shop.While/When/AswhenAswhen5)He was copying a text ___________ his brother came in.
6) Mary learnt a lot _________ she was only 7.
7) _______________ I was drinking, father came in.
8) They bought many food ________________ Mike was studying.
9) ___________________ the thief was stealing the DVD, a lot of people came in.
10) __________he fell down, he came up with an idea.
whenwhenWhile/whenwhile/whenWhile/whenWhen
Thank you!