when与while引导时间状语从句的区别

1、2013八下unit5过去进行时与when、while,（一）含义及构成 过去进行时表示过去某一时刻或某一段时间正在进行或发生的动作，其结构为：was / were + v. ing。 i/he/she/it was +v-ing (第一三人称单数用was) we/you/they +v-ing,过去进行时,（1）过去进行时的否定句结构为：was / were+ not +v. -ing ，was与not常缩写为wasnt，were与not常缩写为werent。 （2）过去进行时的一般疑问句结构为：was / were +主语+ v. -ing+其他？ （3）过去进行时的特殊疑问句结构为：疑问

2、词+ was / were+主语+v. -ing+其他？,（二）用法 1. 表示过去某一时刻或某一段时间正在进行或发生的动作。与过去某一特定的时间状语连用，常见的有：at 3 oclock yesterday afternoon, in those days, at this time yesterday等。 2. 表示过去一个动作发生时，另一个动作正在进行，持续时间长的动作用过去进行时，常用在while引导的时间状语从句中。,. 用所给词的适当形式填空 1. i _ (help) my mother with housework at ten oclock last sunday. 2. t

3、he girl _ (have) a piano lesson at this time yesterday.,过去进行时的用法,was helping,was having,3. they _ (talk) about the film when the teacher came in. 4. while he _ (wait) for the bus, he read a newspaper. 5. he said he was _ (leave) for shanghai soon.,were talking,was waiting,leaving,. 句型转换 1. kate was

4、drawing pictures when her mother came back. （改为否定句） kate _ _ pictures when her mother came back. 2. she was babysitting her sister at this time yesterday. （改为一般疑问句） _ she _ her sister at this time yesterday?,wasnt drawing,was babysitting,3. they were having a party when i knocked at the door. （就划线部分

5、提问） _ _ they _ when you knocked at the door?,what were doing,. 用when或while填空 1. what were you doing _ the earthquake happened? 2. _ i was shopping in the supermarket, i met my friend nancy.,when,while,3. i was sleeping _ my cousin came to see me. 4. my mother was doing the housework _ i was doing my

6、 homework. 5. _ the alien was in the shop, the girl called the police.,when,while,while,when and while,both of them mean ”当的时候”.,are they the same? no ！,when引导的时间状语从句可以表示一个时间点,也可以表示一个时间段。从句中可以用短暂性动词,也可以用延续性动词。从句中的动作既可与主句的动作同时发生，又可在主句的动作之前或之后发生。 it was snowing when we got to the airport. 我们到达机场时, 天正下

7、着雪。 my key dropped on the ground when i was walking in the park. 我在公园散步时, 钥匙掉在了地上。,when,while,while引导的时间状语从句常指一个时间段,从句中的动词必须为延续性动词。while有时还可表示主句的动作与从句的动作同时发生。 while he was reading, the phone rang. 他正在看书时, 电话铃响了。 some students were reading while others were writing. 一些学生在读书, 另一些学生在写字。,tips:,当时间状语从句中的

8、动作与主句中的动作同时发生，且从句动作为延续性动词时，when 与while都可以使用。 when 说明从句的动作各主句的动作可以是同时发生，也可以是先后发生，while则强调主句的动作在从句动作的发生过程中发生或者主从句动作同时发生。,tips:,通常情况下when能替代while, 但while不能替代when. 当从句和主句都用过去进行时的时候，多用while引导。,(2009四川泸州) what were you doing _ zhang fan came in? a. when b. while c. where 【解析】三个选项分别意为“当时”、“与同时”、“哪里”，结合题意“当

9、张凡进来时，你正在做什么？”可排除b、c二项，故选a。,1. what _ (be) you _ (do) when he arrived? 2. jim_ (sleep) when i came in. 3. they _ (watch) tv at 8:00 yesterday evening. 4. now he _ (read) and _.,were,doing,was sleeping,were watching,is reading,writing,a. fill in the blanks with the given words.,b. translate these sen

10、tences into english.,1. 上课铃响时，你在干什么？ what _ you _when the class bell rang? 2. 当我妈妈进来时我正在看书。 i _when my mother came in. 3. 昨天晚上十点钟她正在做饭。 she _ at ten oclock _.,were,doing,was reading,was cooking,last night / yesterday evening,4. 当天开始下雨时, 孩子们正在玩游戏。 the children _ games when it _ to rain. 5. 当我进来时，那只猫逃跑了。 the cat _ when i _.,were playing,began,ran away,came in,6. 飞机在伦敦着陆时, 天正下着雨。 it _ when the plane _ in london. 7. 电话铃响的时候, 我正在吃早饭。 i