some time sometime sometimes sometimes 练习

some time sometime sometimes sometimes 练习

_______ I go to school on foot .

We will meet again _____ next week .

Lenin stayed in London for _________.

David has been to the museum _________.

We visited the small town ________ last year and stayed there for _________.

2010 灿烂在六月

1.He has seen the film ______ , so he won’t go to the cinema with us . A. some time B.

sometime C. sometimes D. sometimes

2.

WHEN与WHILE用法区别

WHEN与WHILE用法区别 when, while这三个词都有"当……时候"之意，但用法有所不同，使用时要特别注意。 ①when意为"在……时刻或时期"，它可兼指"时间点"与"时间段"，所引导的从句的动词既可以是终止性动词，也可是持续性动词。如： When I got home, he was having supper.我到家时，他正在吃饭。 When I was young, I liked dancing.我年轻时喜欢跳舞。 ②while只指"时间段"，不指"时间点"，从句的动词只限于持续性动词。如：While I slept, a thief broke in.在我睡觉时,盗贼闯了进来。 辨析 ①when从句与主句动作先后发生时，不能与while互换。如： When he has finished his work, he takes a short rest.每当他做完工作后，总要稍稍休息一下。(when = after) When I got to the cinema, the film had already begun.当我到电影院时，电影已经开始了。(when=before) ②when从句动词为终止性动词时，不能由while替换。如： When he came yesterday, we were playing basketball.昨天他来时，我们正在打篮球。 ③当从句的谓语是表动作的延续性动词时，when, while才有可能互相替代。如：While / When we were still laughing, the teacher came in.正当我们仍在大声嬉笑时，老师进来了。 ④当从句的谓语动词是终止性动词，而且主句的谓语动词也是终止性动词 时,when可和as通用，而且用as比用when在时间上更为紧凑，有"正当这时"的含义。如： He came just as (or when) I reached the door.我刚到门那儿，他就来了。 ⑤从句的谓语动词如表示状态时，通常用while。如： We must strike while the iron is hot.我们应该趁热打铁。 ⑥while和when都可以用作并列连词。

it的用法归纳

?Never be afraid of grammar ?Collect some examples; ?Watch them very carefully; ?Find out something in common; ?Try to use the rules ---- practise. it用法完全归纳 一、it 作人称代词的用法 1.指事物 作为人称代词，it 可以除人以外的一切事物或动物。如： I dropped my watch and it broke. 我把手表掉在地上摔坏了。 It’s hard work, but I enjoy it. 工作很辛苦，可是我乐意干。 “Where is the dog?”“It’s in the bedroom. ”“狗在哪?”“在卧室里”。 2.指人 it 指人主要用于指不性别不明的婴儿或用于确认某人的身份。如： Is it a boy or a girl? 是男孩还是女孩? There is a knock on the door. It must be the postman. 有人在敲门，一定是邮递员。 【说明】在答语中，常用来指本人，如说It’s me。

3.代替某些代词 代词it 还可用于代替指示代词this, that 以及复合不定代词something, anything, nothing等。如： “What’s this?”“It’s a new machine. ”“这是什么?”“是一种新机器”。 Nothing is wrong, is it? 没出什么问题，是吗? 二、it 作非人称代词的用法 1.基本用法 it 作非人称代词的用法，主要用于指时间、距离、价值、天气、气候及温度等自然现象。如： It’s too late to go there now. 现在去那儿已经太迟了。 It rained all day yesterday. 昨天下了一天的雨。 It can get very hot here. 这里有时会很热。 2.用于某些句型 It’s time for sth. 该做某事了。 It’s time to do sth. 该做某事的时候了。 It’s time for sb to do sth. 某人该干某事了。 It’s (about / high) time + that-从句. 某人该做某事了。(从句谓语用过去式，有时也用“should+动词原形”) It’s first (second) time + that-从句. 某人第几次干某事。(从句谓语用现在完成时)

When引导的定语从句与时间状语从句的区分

一、从句是如何出题的？ 1. 时态 2. 考连接词 3. 考语言顺序 二、学好从句的两个基本条件 1. 时态 2. 从句的三个必须:①必须是句子；②必须有连接词；③必须是陈述句 三、状语从句、宾语从句、定语从句重点 1.如何判断何种从句 2. 从句的时态 3. 从句的连接词与扩展 4. 经典单选、从句与选词、长句子分析 四、如何判断三种从句 1. 状语从句无先行词 2. 宾语(表语)从句无先行词有动词或词组 3. 定语从句先行词多为名词或代词 一、When引导的定语从句与时间状语从句的区分 1. when的译法不同。在时间状语中，when 翻译成“当……的时候” I want to be a teacher when I grow up. 当我长大的时候，我要做一名老师。在定语从句中，when不翻译。I won't forget the day when he says he loves me. 我不会忘记他说爱我的那一天。 2. 在时间状语中，when从句前面或后面是句子；定语从句中，when 从句不能位于句首，且通常when前为表示时间的名词day、year等。 3. when在从句的作用不同。在时间状语从句中，when是连词，只起连接主句和从句的作用，不做从句的任何成分。不过when引导的时间状语从句修饰主句的谓语，做主句的时间状语。 在定语从句中，when是关系副词，在从句中代替先行词做从句的时间状语，修饰从句的谓语。 例1 I will always remember the days when I lived with my

grandparents in the country. 例2 I always remember the days in the country when I see the photo of my grandparents. 点评：例1意为“我会永远记得跟我祖父母一起住在乡下的那些日子”，其中when 引导的是一个定语从句, 修饰the days, when在从句中作时间状语。例2意为“当我看到祖父母的照片时，总是会想起在乡下的那些日子”，其中when 引导的从句并不修饰前面的名词the country，因此可判定为时间状语从句。 例1中的when可用in which替代，即从句可改为...in which I lived with my grandparents in the country. 例2中从句前有名词，但根据句意可 知并不是从句所修饰的对象，也不能用“介词+ which”来替代。 二、判断关系代词与关系副词 方法一：用关系代词，还是关系副词完全取决于从句中的谓语动词。及物动词后面无宾语，就必须要求用关系代词；而不及物动词则要求用关系副词。例如： This is the mountain village where I stayed last year. 这是我去年呆过的山村。 I'll never forget the days when I worked together with you. 我永远不会忘记与你共事的日子。 判断改错： 1. This is the mountain village where I visited last year. 2. I will never forget the days when I spent in the countryside. 3. This is the mountain village （which）I visited last year.

when和while区别及专项练习---含答案

when和while用法区别专项练习 讲解三例句： 1. The girls are dancing while the boys are singing. 2. Kangkang’s mother is cooking when he gets home. 3. When/While Kangkang’s mother is cooking, he gets home. 一、用when或者while填空 Margo was talking on the phone, her sister walked in. we visited the school, the children were playing games. · Sarah was at the barber’s, I was going to class. I saw Carlos, he was wearing a green shirt. Allen was cleaning his room, the phone rang. Rita bought her new dog; it was wearing a little coat. 7. He was driving along ________ suddenly a woman appeared. 8. _____ Jake was waiting at the door, an old woman called to him. 9. He was reading a book ______suddenly the telephone rang. 10. ______ it began to rain, they were playing chess. [ 二、用所给动词适当形式填空 11. While Jake __________ (look) for customers, he _______ (see) a woman. 12. They __________ (play) football on the playground when it _____ (begin) to rain. 13. A strange box ________ (arrive) while we _________ (talk). 14. John ____________ (sleep) when someone __________ (steal) his car. 15. Father still (sleep) when I (get) up yesterday morning. 16. Grandma (cook) breakfast while I (wash) my face this morning. 17. Mother (sweep) the floor when I (leave) home. ~ 18. I (read) a history book when someone (knock ) at the door. 19. Mary and Alice are busy (do) their homework. 20. The teacher asked us (keep) the windows closed. 21. I followed it (see) where it was going. 22. The students (play) basketball on the playground from 3 to 4 yesterday afternoon. / 三、完成下面句子，词数不限 1.飞机在伦敦起飞时正在下雨。 It when the plane in London. 2.你记得汶川大地震时你在做什么吗 Do you remember what you when Wenchuan Earthquake . 3.当铃声想起的时候，我们正在操场上玩得很开心。 We on the playground when the bell . 4.当妈妈下班回家时，你在做什么 % when Mum from work 5.当我在做作业时，有人敲门。 I was doing my homework, someone

过去进行时、when和while引导时 间状语从句的区别

过去进行时过去进行时表示过去某一时刻或者某段时间正在进行或发生的动作，常和表过去的时间状语连用，如： 1. I was doing my homework at this time yesterday. 昨天的这个时候我正在做作业。 2. They were waiting for you yesterday. 他们昨天一直在等你。 3. He was cooking in the kitchen at 12 o'clock yesterday. 昨天12点，他正在厨房烧饭。 过去进行时的构成： 肯定形式：主语+was/were+V-ing 否定形式：主语+was not (wasn't)/were not (weren't)+V-ing 疑问形式：Was/Were+主语+V-ing。 基本用法： 1. 过去进行时表示过去某一段时间或某一时刻正在进行的动作。常与之连用的时间状语有，at that time/moment, (at) this time yesterday (last night/Sunday/week…), at+点钟+yesterday (last night / Sunday…)，when sb. did sth.等时间状语从句，如： 1）What were you doing at 7p.m. yesterday? 昨天晚上七点你在干什么？ 2）I first met Mary three years ago. She was working at a radio shop at the time. 我第一次遇到玛丽是在三年前，当时她在一家无线电商店工作。 3）I was cooking when she knocked at the door. 她敲门时我正在做饭。 2. when后通常用表示暂短性动词，while后通常用表示持续性动词，而while所引导的状语从句中，谓语动词常用进行时态，如： When the car exploded I was walking past it. = While I was walking past the car it exploded. 3. when用作并列连词时，主句常用进行时态，从句则用一般过去时，表示主句动作发生的过程中，另一个意想不到的动作发生了。如： I was walking in the street when someone called me. 我正在街上走时突然有人喊我。 4. when作并列连词，表示“（这时）突然”之意时，第一个并列分句用过去进行时，when引导的并列分句用一般过去时。如：

-it的用法及强调句型(精心整理)

it的用法及强调句型 it的用法 一、it作指示代词【完成句子】用one，ones，it，that，those填空 (1) — I can't find my watch. —You haven't found ______？If you want to buy a new ______，I suggest you buy ______ made in China. (2) We've got a big cup and two small ______. (3) The weight of an elephant is much greater than ______ of a tiger. (4) The books on the first shelf are easier than ______ on the second shelf. (5) The boy told his story and ______ of the girl upstairs. 【答案】(1) it; one; one (2) ones(3) that (4) those / the ones (5) that / the one 【结论1】 ①指代上文提过的事物时，it指的是同名同物，相当于the＋名词； ②one指的是同名异物，表示单数可数名词相当于a ＋名词；a / an＋形容词＋one等于a / an＋形容词＋名词；复数形式用ones； ③that后面常有后置定语，有特指意义，代替不可数名词或单数可数名词，相当于the＋ 名词； ④复数名词用those，相当于the ones。 【例句观察】— Someone is knocking at the door. Who is it? — It must be Leo. He said he'd come to see me. 【结论2】it指代人时，常指小孩或身份不明的人。 【例句观察】It's too quiet in the room. Everyone just keeps silent. 【结论2】it可用以指代环境或情况。 (6)— What time is it now? — It's half past seven. (7)— It is spring now and it's warm these days. 【结论3】it可用以指代时间、季节、天气或距离。 【注意】it指代时间时，有如下一些句型： (1) It is time for sth. (for sb.)to do sth. / that－从句(should do / did, 必须用虚拟语气) 例：① It's time for lunch. ② It's time for us to clean the house. ③ It's time that we should clean the house. ＝It's time that we cleaned the house. (2) It is / has been ＋some time ＋since－从句(从句用一般过去时) It is 10 years since I graduated from college. (3) It / This/That is the first / second time that－从句(必须使用现在完成时)这是某人 第……次做了某事。 It / This/That was the first / second time that－从句(必须使用过去完成时) 例：①It is the second time that she has visited the Great Wall. ②This was the first time that I had come late to school. (4) It was ＋时间点＋when －从句 例：It was evening when we got home. ＝It was evening in which we got home. (5) It was / will be ＋some time ＋before －从句 例：①过了5年他们才从北大毕业。 It was five years before they finally graduated from Beijing University. ②不久，我们就要从我们学校毕业了。 It won't be long before we graduate from our school. 二、it作形式主语 1.代替主语从句 ①It is clear ( obvious，true，possible certain....) that ..... “清楚（显然，真的，肯定．．．）” ②. It is important ( necessary，right，strange，natural...) that ... that 后的从句中要用虚拟语气（should + 动词原形），should 可以省去，建议记住该句型中的形容词。 It is important that we (should) learn English well.

when和while的区别是

Period____8______ in Unit ___6_________ （Period_____20_____Week 4-6）Subject _Grammar (B) Teaching aims To use the Past Continuous Tense with while and when correctly Teaching interesting points of this class: The differences of when and while in Past Continuous Tense Teaching steps: I. Cooperation and intercourse 1. Check the preparation 2. Discuss in groups II. Question and explanation Check the exercises on page 101, and explain the differences between when and while. when和while的区别是： when只能用于一般时态 while可以用于进行时态 when conj. 在...的时候, 当…的时候 when 在绝大多数情况下，所引导的从句中，应该使用非延续性动词（也叫瞬间动词） 例如：I'll call you when I get there. 我一到那里就给你打电话 I was about to go out when the telephone rang.我刚要出门，电话铃就响了。 但是，when 却可以be 连用。 例如：I lived in this village when I was a boy. 当我还是个孩子的时候我住在这个村庄里。 When I was young, I was sick all the time. 在我小时候我总是生病 while 当...的时候 While he was eating, I asked him to lend me $2. 当他正在吃饭时,我请他借给我二美元。While I read, she sang. 我看书时，她在唱歌。 while 的这种用法一般都和延续性动词连用 while 可以表示“对比‘，这样用有的语法书认为是并列连词 Some people like coffee, while others like tea. 有些人喜欢咖啡, 而有些人喜欢茶。 as 当...之时，一边......一边....... I slipped on the ice as I ran home. 我跑回家时在冰上滑了一跤 He dropped the glass as he stood up. 他站起来时，把杯子摔了。 She sang As she worked. 她一边工作一边唱歌。 III. Rumination and evaluation when, as, while这三个词都可以引出时间状语从句，它们的差别是：when 从句表示某时刻或一段时间as 从句表示进展过程，while 只表示一段时间 When he left the house, I was sitting in the garden. 当他离开家时，我正在院子里坐着。 When he arrived home, it was just nine o'clock.

when 和while的用法区别

when 和while的用法区别 ①when是at or during the time that, 既指时间点，也可指一段时间； while是during the time that，只指一段时间，因此when引导的时间状语从句中的动词可以是终止性动词，也可以是延续性动词，而while从句中的动词必须是延续性动词。 ②when 说明从句的动作和主句的动作可以是同时，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的过程中或主从句两个动作同时发生。 ③由when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，两句都用过去进行时的时候，多用while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： While we were talking, the teacher came in. b. They were singing while we were dancing. ④when和while 还可作并列连词。when表示“在那时”；while表示“而，却”，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。 when，while，as引导时间状语从句的区别 when，while，as显然都可以引导时间状语从句，但用法区别非常大。 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。 ①Why 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？ ②Sorry，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。 ③Strike 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。 ④The students took notes as they listened．（listen为延续性动词）学生们边听课边做笔记。 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。 ①When 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。 ②When I got to the airport，the guests had left．（got to后发生）当我赶到飞机场时，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用法区别

While和When在过去进行时中两者的区别如下： ①when是at or during the time that, 既指时间点，也可指一段时间；while是during the time that，只指一段时间，因此when引导的时间状语从句中的动词可以是终止性动词，也可以是延续性动词，而while 从句中的动词必须是延续性动词。 ②when 说明从句的动作和主句的动作可以是同时，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的过程中或主从句两个动作同时发生。 ③由when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，两句都用过去进行时的时候，多用while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： While we were talking, the teacher came in. b. They were singing while we were dancing. ④when和while 还可作并列连词。when表示“在那时”；while表示“而，却”，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。 when; while 当……时候 while能用when代替; 但是when却不一定能用while代替. while+从句, 动作一定会延续 when+延续性动词/瞬间动词; when he arrived

It的用法及典型句型归纳. 个人总结

It的用法及典型句型归纳 一、人称代词it的最基本用法是作代词，主要指刚提到的事物，想法，以避免重复;也可以指性别不明或性别被认为是不重要的人或动物；未指明但谈话双方都明白的事情或情况。 ①They watched the train until it disappeared in the distance. ②Is this your dog？No, it isn’t. ③I hate it when people talk with a full mouth.． 二、.非人称代词.it有时并不指具体的东西而泛指天气、时间、日期、距离、价值、度量、温度、环境等： It is a lovely day, isn’t it? // It was nearly midnight when she came back. It is April First today. // It is some 3000 kilometers from A to B. It is three dollars. // Today it is 30 degrees centigrade. 三、作形式主语，替代主语从句，动词不定式，或动名词短语 1.作形式主语替代主语从句 ⑴It is clear ( obvious，true，possible，certain....) that ＂┅清楚的（显然的，真的，可能的,肯定的．．．）＂ ⑵It is important ( necessary，right，strange，natural...) that + (should ) do (虚拟语气) ┅是重要的(必要的,对的,奇怪的,自然的┅) ⑶It is said (reported/ learned/believed/thought/known/told/hoped.....) that = sb / sth is said (reported/ believed /thought…) to do( to be doing/ to have done) sth ＂据说（据报道，据悉．．．）＂。 ⑷It is suggested ( advised/ ordered / demanded/ insisted/ commanded... ) that +(should ) do ＂据建议；有命令．． ⑸It is a pity ( a shame /an honour/a good thing/a fact,/a surprise/... ) that that后的从句一般用虚拟语气（should + 动词原形），should可省去．表示出乎意料，常译为＂竟然＂。没有这种意义时，则不用虚拟语气。 小练一下： It is very clear that he’s round and tall like a tree. = It is important that we (learn) English well. It is necessary that he (remember) these words. It is said that he has come to Beijing. = It is reported that another earth satellite has been put into orbit. = It is suggested that the meeting ( put off). It was ordered that we (arrive) there in two hours. It is a pity that such a thing ( happen) in your class. It is a pity that he (be) ill. 2.作形式主语替代不定式 . ⑴It is kind ( of sb. ) to do sth.= sb be kind to do sth.一般都是表示人的特性的形容词。如： bad /brave /careless/ clever /cruel / foolish / good （好心的）/ honest/ kind / lazy / modest/ naughty/ nice（有教养的）/polite/ rude / silly / stupid / wise ，等。 Eg. It is kind of you to give me a hand. = ⑵It is necessary ( for sb. ) to do sth. .不定式的逻辑主语是由for引起。常见的形容词有： Important/ necessary/ natural/ easy / safe / common / normal / hard / difficult / dangerous/ unusual/ rare / impossible / pleasant Eg. It is important for her to come to the party.

过去进行时、when和while引导时间状语从句的区别

过去进行时 过去进行时表示过去某一时刻或者某段时间正在进行或发生的动作，常和表过去的时间状语连用，如： 1. I was doing my homework at this time yesterday. 昨天的这个时候我正在做作业。 2. They were waiting for you yesterday. 他们昨天一直在等你。 3. He was cooking in the kitchen at 12 o'clock yesterday. 昨天12点，他正在厨房烧饭。 过去进行时的构成： 肯定形式：主语+was/were+V-ing 否定形式：主语+was not (wasn't)/were not (weren't)+V-ing 疑问形式：Was/Were+主语+V-ing。 基本用法： 1. 过去进行时表示过去某一段时间或某一时刻正在进行的动作。常与之连用的时间状语有，at that time/moment, (at) this time yesterday (last night/Sunday/week…), at+点钟+yesterday (last night / Sunday…)，when sb. did sth.等时间状语从句，如： 1）What were you doing at 7p.m. yesterday? 昨天晚上七点你在干什么？ 2）I first met Mary three years ago. She was working at a radio shop at the time. 我第一次遇到玛丽是在三年前，当时她在一家无线电商店工作。 3）I was cooking when she knocked at the door. 她敲门时我正在做饭。 2. when后通常用表示暂短性动词，while后通常用表示持续性动词，而while所引导的状语从句中，谓语动词常用进行时态，如： When the car exploded I was walking past it. = While I was walking past the car it exploded. 3. when用作并列连词时，主句常用进行时态，从句则用一般过去时，表示主句动作发生的过程中，另一个意想不到的动作发生了。如： I was walking in the street when someone called me. 我正在街上走时突然有人喊我。 4. when作并列连词，表示“（这时）突然”之意时，第一个并列分句用过去进行时，when引导的并列分句用一般过去时。如： 1）I was taking a walk when I met him. 我正在散步，突然遇见了他。 2）We were playing outside when it began to rain. 我们正在外边玩，这时下起雨来了。 过去进行时和一般过去时的用法比较： 1）过去进行时表示过去正在进行的动作，而一般过去时则表示一个完整的动作。 例如：They were writing letters to their friends last night. 昨晚他们在写信给他们的朋友。（没有说明信是否写完） They wrote letters to their friends last night.

while、when和as的用法区别

as when while 的区别和用法 as when while的用法 一、as的意思是“正当……时候”,它既可表示一个具体的时间点，也可以表示一段时间。as可表示主句和从句的动作同时发生或同时持续，即“点点重合”“线线重合”；又可表示一个动作发生在另一个动作的持续过程中，即“点线重合”， 但不能表示两个动作一前一后发生。如果主句和从句的谓语动词都表示持续性的动作，二者均可用进行时，也可以一个用进行时，一个用一般时或者都用一般时。 1、As I got on the bus，he got off. 我上车，他下车。（点点重合）两个动作都是非延续性的 2、He was writing as I was reading. 我看书时，他在写字。（线线重合）两个动作都是延续性的 3、The students were talking as the teacher came in. 老师进来时，学生们正在讲话。（点线重合）前一个动作是延续性的，而后一个动作时非延续性的 二、while的意思是“在……同时（at the same time that )”“在……期间(for as long as, during the time that）”。从while的本身词义来看，它只能表示一段时间，不能表示具体的时间点。在时间上可以是“线线重合”或“点线重合”，但不能表示“点点重合”。例如： 1、He was watching TV while she was cooking. 她做饭时，他在看电视。（线线重合） 2、He was waiting for me while I was working. 我工作的时候，他正等着我。（线线重合） 3、He asked me a question while I was speaking. 我在讲话时，他问了我一个问题。（点线重合）

when和while的用法和区别

when和while的用法和区别 while和when都是表示同时，到底句子中是用when还是while主要看从句和主句中所使用的动词是短暂性动作（瞬时动词）还是持续性动作。 1、若主句表示的是一个短暂性的动作，而从句表示的是一个持续性动作时，两者都可用。如：He fell asleep when [while] he was reading. 他看书时睡着了。 I met him when [while] I was taking a walk in the park. 我在公园散步时遇到了他。 2、若主、从句表示两个同时进行的持续性动作，且强调主句表示的动作延续到从句所指的整个时间，通常要用while。如： Don’t talk while you’re eating. 吃饭时不要说话。 I kept silent while he was writing. 在他写的时候，我默不作声。 3、若从句是一个短暂性动作，而主句是一个持续性动作，可以when 但不用while。如：When he came in, I was listening to the radio. 他进来时，我在听收音机。 It was raining hard when we arrived. 我们到达时正下着大雨。 4、若主、从句表示的是两个同时(或几乎同时)发生的短暂性动作，一般要用when。如： I thought of it just when you opened your mouth. 就在你要说的时候，我也想到了。 至于什么是短暂性动作，什么是持续性动作，其实有个很简单的规律。就是如果是进行时态，一般是持续性的。如果是过去式，一般是短暂性动作。 对于，填写when还是while的问题，通常首先看主句和从句中的时态，再根据以上4个规律来判断填写那个单词。 When和While的区别 通常when 后面接一般过去时while 后面接过去进行时 ①when是at or during the time that, 既指时间点，也可指一段时间，while是during the time that，只指一段时间，因此when引导的时间状语从句中的动词可以是终止性动词，也可以是延续性动词，而while从句中的动词必须是延续性动词。 ②when 说明从句的动作和主句的动作可以是同时，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的过程中或主从句两个动作同时发生。 ③由when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，两句都用过去进行时的时候，多用while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： While we were talking, the teacher came in. b. They were singing while we were dancing. ④when和while 还可作并列连词。when表示“在那时”；while表示“而，却”，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.