B过去进行时whenas和while的区别PPT课件

1、 由由when引导的时间状语从句，主句用过去进行时，引导的时间状语从句，主句用过去进行时，从句应用一般过去时；如果从句和主句的动作同时发生，从句应用一般过去时；如果从句和主句的动作同时发生，两句都用过去进行时的时候，多用两句都用过去进行时的时候，多用while引导，如：引导，如： a. When the teacher came in, we were talking. 当此句改变主从句的位置时，则为：当此句改变主从句的位置时，则为： While we were talking, the teacher came in. b. They were singing while we were d

2、ancing. when和和while 还可作并列连词。还可作并列连词。when表示表示“在那在那时时”；while表示表示“而，却而，却”，表对照关系。如：，表对照关系。如： a. The children were running to move the bag of rice when they heard the sound of a motor bike. 孩子们正要跑过去搬开那袋米，这时他们听到了摩托车孩子们正要跑过去搬开那袋米，这时他们听到了摩托车的声音。的声音。 b. He is strong while his brother is weak. 他长得很结实，而他弟弟却很瘦弱

3、。他长得很结实，而他弟弟却很瘦弱。 第1页/共16页 一、when可以和延续性动词连用，也可以和短暂性动词连用；而while和as只能和延续性动词连用。 Why do you want a new job when youve got such a good one already？（get为短暂性动词）你已经找到如此好的工作，为何还想再找新的？ Sorry，I was out when you called me（call为短暂性动词）对不起，你打电话时我刚好外出了。 Strike while the iron is hot（is为延续性动词，表示一种持续的状态）趁热打铁。 The stud

4、ents took notes as they listened（listen为延续性动词）学生们边听课边做笔记。 第2页/共16页 二、when从句的谓语动词可以在主句谓语动作之前、之后或同时发生；while和as从句的谓语动作必须是和主句谓语动作同时发生。 1从句动作在主句动作前发生，只用 when。 When he had finished his homework，he took a short rest（finished先发生）当他完成作业后，他休息了一会儿。 When I got to the airport，the guests had left（got to后发生）当我赶到飞机

5、场时，客人们已经离开了。 2从句动作和主句动作同时发生，且从句动作为延续性动词时，when，while，as都可使用。 When While As we were dancing，a stranger came in（dance为延续性动词）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（make为延续性动词）当她在打电话时，我正在写信。 第3页/共16页when 和while 的区别1.When的用法比较活， 用在状语从句中，两边的时态可以相等. 1) He was singi

6、ng when I was reading. 2) Father is cooking when Tom is sleeping. 3) Please say hello to Mike when you see him.第4页/共16页when两边的时态也可以不等1)Kate was swimming when her parents came back.2)They were trying to run away when the policeman broke into the house.3)The light went off when they were talking.第5页/共

7、16页while连接的句子，后面必须用进行时（现在/过去进行时） 1)A car hit her while she was thinking about a question.2)The books fell off from the shelf while they were listening to the radio.3)While we are playing football, a noise comes from downstairs.小结：用while 和when 填空，看看它们后面的句子的时态。如果是过去时，必须用when. 如果是进行时，必须用while（没有while选项

8、的时候用when)第6页/共16页小结：在作“当时候”时，when可以替换while. 1)Mary was happy while/when she was doing her homework.2)When/while they are watering flowers, a stranger shout at them.While 还有 “然而”的意思。此时不能用when 代替。1） He has a good chance to be the famous player while he wasted it.2) We could come to see the film yester

9、day while Tom lost the tickets.第7页/共16页用while 和when填空1）He was copying a text _ his brother came in.2) Mary learnt a lot _ she was only 7.3) _ I was drinking, father came in.4) They bought many food _ Mike was studying.5) _ the thief was stealing the DVD, a lot of people came in.6) _ he fell down, he

10、 came up with an idea.whenwhenWhile/whenwhile/whenWhile/whenWhen第8页/共16页 3 3当主句、从句动作同时进行，从句动作的时间概念当主句、从句动作同时进行，从句动作的时间概念淡化，而主要表示主句动作发生的背景或条件时，只能淡化，而主要表示主句动作发生的背景或条件时，只能用用 asas。这时，。这时，asas常表示常表示“随着随着”；“一边一边，一边一边”之意。之意。 AsAs the time went on the time went on，the weather got the weather got worseworse（

11、asas表示表示“随着随着”之意）之意） The atmosphere gets thinner and thinner The atmosphere gets thinner and thinner asas the height increasesthe height increases随着高度的增加，大气越来随着高度的增加，大气越来越稀薄。越稀薄。 AsAs years go by years go by，China is getting stronger China is getting stronger and richerand richer随着时间一年一年过去，中国变得越来随着时

12、间一年一年过去，中国变得越来越富强了。越富强了。 The little girls sang The little girls sang asas they went they went小姑娘小姑娘们一边走，一边唱。们一边走，一边唱。 The sad mother sat on the roadsideThe sad mother sat on the roadside，shouting shouting asas she was crying she was crying伤心的妈妈坐在路边，伤心的妈妈坐在路边，边哭边叫。边哭边叫。 第9页/共16页 4 4在将来时从句中，常用在将来时从句中，

13、常用whenwhen，且从句须用一，且从句须用一般时代替将来时。般时代替将来时。 You shall borrow the book You shall borrow the book whenwhen I have I have finished reading itfinished reading it在我读完这本书后，在我读完这本书后，你可以借阅。你可以借阅。 WhenWhen the manager comes here for a the manager comes here for a visit next weekvisit next week，I Ill talk with h

14、im ll talk with him about thisabout this下周，经理来这参观时，我会和下周，经理来这参观时，我会和他谈谈此事。他谈谈此事。 第10页/共16页 as, when, whileas, when, while都表示主、从句的动作或状态同时发生，但三都表示主、从句的动作或状态同时发生，但三者意义不尽相同。者意义不尽相同。asas和和whenwhen引导的从句既可表示一点时间，也可引导的从句既可表示一点时间，也可表示一段时间，从句中的谓语动词既可以是持续性动词，也可以表示一段时间，从句中的谓语动词既可以是持续性动词，也可以为短暂性动词，经常可以互换使用；为短暂性动

15、词，经常可以互换使用；whilewhile引导的从句通常表示引导的从句通常表示一段时间，从句中宜用持续性动词作谓语。当从句中的谓语动词一段时间，从句中宜用持续性动词作谓语。当从句中的谓语动词为持续性动词时，这三者可以通用（前面例句中已有体现），再为持续性动词时，这三者可以通用（前面例句中已有体现），再如：如： Mother was worried because little Alice was ill, Mother was worried because little Alice was ill, especially especially as / when / whileas / wh

16、en / while father was away in father was away in France.France.妈妈担心，因为小艾丽思病了，特别是当父亲远在法国妈妈担心，因为小艾丽思病了，特别是当父亲远在法国的时候。的时候。 如果从句和主句要表示一个人的两个动作交替进行或同时完成时，如果从句和主句要表示一个人的两个动作交替进行或同时完成时，则多用则多用asas，可译为，可译为“一边一边.，一边，一边.”。例如：。例如： He looked behind from to time He looked behind from to time asas he went. he went

17、.他一边走，一他一边走，一边不时地往后看。边不时地往后看。 AsAs time goes on, it time goes on, its getting warmer and warmer.s getting warmer and warmer.随着随着时间的推移，天气变得越来越暖了。时间的推移，天气变得越来越暖了。 I thought of it just I thought of it just asas you opened your mouth. you opened your mouth.你一张你一张嘴我就知道你要说什么。（若表示两个短促动作几乎同时发生时，嘴我就知道你要说什么。（

18、若表示两个短促动作几乎同时发生时，用用asas的场合多于的场合多于when.when.） 第11页/共16页 当主从句之间表示转折或对比关系时，多用当主从句之间表示转折或对比关系时，多用while, while, 不不用用asas或或whenwhen。如：。如： She thought I was talking about her daughter, She thought I was talking about her daughter, whilewhile in fact, I was talking about my in fact, I was talking about my d

19、aughter.daughter.她以为我在谈论她女儿，而事实上，我在谈她以为我在谈论她女儿，而事实上，我在谈论我的女儿。论我的女儿。 如果表示从句的动作在主句的动作如果表示从句的动作在主句的动作“之前之前”或或“之后之后”发生时，多用发生时，多用whenwhen（=after=after）, , 不用不用asas或或 whilewhile。此。此外，外，whenwhen还含有还含有“at that momentat that moment”的意思（的意思（= and = and thenthen），引起的句子不能放在句首，也不能用），引起的句子不能放在句首，也不能用as, as, while

20、while来替换。例如：来替换。例如： He was about to leave He was about to leave whenwhen the telephone rang. the telephone rang.他正要离开，忽然电话铃响了。他正要离开，忽然电话铃响了。 We were watching TV We were watching TV whenwhen suddenly the lights suddenly the lights went out.went out.我们正在看电视，突然灯灭了。我们正在看电视，突然灯灭了。 They had just arrived home They had just arrived home whenwhen it began to it began to rain.rain.他们刚到家，天就开始下雨了。他们刚到家，天就开始下雨了。第12页/共16页as soon as 的用法 as soon as连接的时间状语从句中，指未发生的动作，规律是：主句一般将来时，从句用一般现在时代替一般将来时 （主将从现） I will tell him the news as soon as he comes