【文章內(nèi)容簡(jiǎn)介】 a letter, the children were playing ，孩子們都在外面玩。（線線重合）此句中的when從句的動(dòng)作表示的是一段時(shí)間，故可用as 或 while代替。版本三一、根據(jù)從句動(dòng)作的持續(xù)性來(lái)區(qū)分“主短從長(zhǎng)”型：即主句是一個(gè)短暫性動(dòng)作，而從句是一個(gè)持續(xù)性動(dòng)作，此時(shí)三者都可用。如：Jim hurt his arm while［when，as］ he was playing 。As［When，While］ she was waiting for the train，she became very ，變得很不耐煩。注意：as 用于引出一個(gè)持續(xù)性動(dòng)詞表示“在??期間”時(shí)，其謂語(yǔ)通常只能是那些含有動(dòng)作(action)和發(fā)展(development)意味的動(dòng)詞，一般不能是那些不用于進(jìn)行時(shí)態(tài)的動(dòng)詞(如 be，seem，love，want，agree，see，know，have等)，所以下面一句中的 while 不能換為 as： A：I’m going to the post 。B：While you are there，can you get me some stamps？當(dāng)你在郵局時(shí)，能幫我買幾張郵票嗎？“主長(zhǎng)從長(zhǎng)”型：即主句和從句為兩個(gè)同時(shí)進(jìn)行的動(dòng)作或存在的狀態(tài)，且強(qiáng)調(diào)主句動(dòng)作或狀態(tài)延續(xù)到從句所指的整個(gè)時(shí)間，此時(shí)通常要用while。I always listen to the radio while I’m 。He didn’t ask me in。he kept me standing at the door while he read the ，他只顧看那張條子，讓我站在門口等著。但是，若主句和從句所表示的兩個(gè)同時(shí)進(jìn)行的動(dòng)作含有“一邊??一邊”之意時(shí)，則習(xí)慣上要用as。如：He swung his arms as he 。I couldn’t remember a story to tell the children, so I made one up as I went ，只好現(xiàn)編現(xiàn)講?！爸鏖L(zhǎng)從短”型：即主句是一個(gè)持續(xù)性動(dòng)作，而從句是一個(gè)短暫性動(dòng)作，此時(shí)可以用as或when，但不能用while。如：It was raining hard when [as] we 。When [As] he came in, I was listening to the ，我在聽收音機(jī)。二、根據(jù)主句與從句動(dòng)作是否同時(shí)發(fā)生來(lái)區(qū)分若主句與從句表示的是兩個(gè)同時(shí)發(fā)生的短暫性動(dòng)作，含有類似漢語(yǔ)“一??就”的意思，英語(yǔ)一般要用as(也可用when)。如：The ice cracked as [when] I stepped onto 。He jumped to his feet as the boss came 。但是，在hardly [scarcely]?when?句式中，不能將when換成as。如： Scarcely had we arrived, when it began to 。若主句與從句表示的是兩個(gè)幾乎同時(shí)發(fā)生的短暫性動(dòng)作，含有類似漢語(yǔ)“剛要??就”“正要??卻”的意思，英語(yǔ)一般要用as(也可用when)，且此時(shí)通常連用副詞just。如： I caught him just when [as] he was leaving the ，我把他截住了。Just as [when] the two men were leaving, a message ，突然有了消息。三、根據(jù)是否具有伴隨變化來(lái)區(qū)分若要表示主句動(dòng)作伴隨從句動(dòng)作同時(shí)發(fā)展變化，有類似漢語(yǔ)“隨著”的意思，英語(yǔ)習(xí)慣上要用as，而不用when或while。如：The room grew colder as the fire burnt ，房間越來(lái)越冷。As time goes by my memory seems to get ，我的記憶力似乎越來(lái)越差。注：若不是引導(dǎo)從句，而是引出一個(gè)短語(yǔ)，則用with，不用as。如：With winter ing on, it’s time to buy warm ，該買暖和衣裳了。The shadows lengthened with the approach of ，影子也逐漸伸長(zhǎng)。四、根據(jù)從句動(dòng)作的規(guī)律性來(lái)區(qū)分若暗示一種規(guī)律性，表示“每當(dāng)??的時(shí)候”，英語(yǔ)一般要用when。如： It’s cold when it 。He smiles when you praise 。五、根據(jù)主從句動(dòng)作的先后順序來(lái)區(qū)分若主句與從句所表示的動(dòng)作不是同時(shí)發(fā)生，而是有先后順序時(shí)，一般要用when。如： When he arrives he’ll tell us all about the ，他會(huì)好好給我們講講那場(chǎng)比賽的情況。When she had finished she waited as though for a ，仿佛是在等候回答似的。六、根據(jù)是否具有“趁機(jī)”意味來(lái)區(qū)分若從句所表示的“當(dāng)??的時(shí)候”具有“趁機(jī)”的意味，則通常用while。如： Strike while the iron is 。I tried to slip the note to him while the teacher wasn’t 。有時(shí)也用when。如：He stole the money when no one was 。The boy looks at her repeatedly when she’s not 。七、根據(jù)是否用作并列連詞來(lái)區(qū)分when可用作并列連詞，表示“這時(shí)(突然)”；while也可以用作并列連詞，表示“而”“卻”(表示對(duì)比)；但as則沒有類似用法。如：I was just about to go to bed when I heard a knock on the ，聽見有人敲門。One person may like to spend his vacation at the seashore, while another may prefer the ，而另一個(gè)人會(huì)喜歡在山里度假。八、根據(jù)所引出的省略句來(lái)區(qū)分as和when之后均可直接跟一個(gè)名詞，構(gòu)成省略句；但是while一般不這樣用。如： As [When] a boy, he lived in 。As [When] still a student, he wrote a ，他就寫了一本小說(shuō)。when和while之后可接現(xiàn)在分詞、介詞短語(yǔ)、形容詞等構(gòu)成省略句，但as一般不這樣用。如：When [While] reading, he fell 。When [While] in trouble, ask her for 。第二篇：While用法小結(jié)While用法小結(jié)：一、while 用作名詞時(shí)，意為“一段時(shí)間，一會(huì)兒”。例如：I stayed there for a short while.（我在那兒呆了一小會(huì)兒。）The postman came a short while ago.（郵遞員剛剛來(lái)過(guò)。）二、while 用作連詞時(shí)，有以下幾種含義：“當(dāng)……時(shí)候，和……同時(shí)”，引導(dǎo)時(shí)間狀語(yǔ)從句。例如：While I was watching TV, the bell rang.（我看電視時(shí)，鈴響了。）Meimei watched TV while she ate her supper.（梅梅邊吃晚飯邊看電視。）“雖然，盡管”，引導(dǎo)讓步狀語(yǔ)從句。例如：While it was late, he went on working.（雖然很晚了，但他還在繼續(xù)工作。）While he is in poor health, he works hard.（雖然他身體不好，但他還是努力工作。） 相當(dāng)于as long as，譯作“只要”。例如：While there is life, there is hope.（有生命，就有希望。）While a spark of life remains, it is a doctor39。s duty to save the patient.（只要病人還有一息生機(jī)，醫(yī)生就有責(zé)任挽救。），相當(dāng)于since，有“既然”的意思。例如：You39。ll never save any money while you39。re so extravagant.（你這么奢侈，永遠(yuǎn)存不下錢來(lái)。）I39。d like to get it settled today while we39。re at it.（既然我們著手干了，我想今天就把它干完。），表示“對(duì)比”關(guān)系。例如：He went out for a walk, while I stayed at home.（他出去散步了，而我卻呆在家里。）I like singing while she likes dancing.（我喜歡唱歌，而她喜歡跳舞。）You like sports, while I prefer music.（你喜歡體育，而我更喜歡音樂(lè)。）三、while 引導(dǎo)狀語(yǔ)從句時(shí)，應(yīng)注意以下幾點(diǎn)： 引導(dǎo)的時(shí)間狀語(yǔ)從句既可放在句首，也可放在句末；而 while 引導(dǎo)的讓步狀語(yǔ)從句一般放在句首，不放在句末。另外，也可以從意義上加以區(qū)分。例如：While he was tired, he went on working.（雖然他累了，但他還是繼續(xù)工作。）（while 引導(dǎo)讓步狀語(yǔ)從句）While he was tired, he would have a rest.（他累了就休息一會(huì)兒。）（while 引導(dǎo)時(shí)間狀語(yǔ)從句） 引導(dǎo)讓步狀語(yǔ)從句時(shí)，如果從句的主語(yǔ)和主句的主語(yǔ)相同，那么從句的主語(yǔ)和謂語(yǔ)動(dòng)詞 be 都可以省略。例如：While he was ill, he went there.（= While ill，he went there.）（雖然他有病，但他還是去那里了。） 和 when 都可以引導(dǎo)時(shí)間狀語(yǔ)從句，但應(yīng)注意：while 引導(dǎo)的時(shí)間狀語(yǔ)從句中的謂語(yǔ)動(dòng)詞必須是延續(xù)性的動(dòng)詞；而 when 引導(dǎo)的時(shí)間狀語(yǔ)從句中的謂語(yǔ)動(dòng)詞既可以是延續(xù)性動(dòng)詞，也可以是非延續(xù)性動(dòng)詞。當(dāng)時(shí)間狀語(yǔ)從句中的謂語(yǔ)動(dòng)詞是延續(xù)性動(dòng)詞時(shí)，while 和 when 可以互相替換。例如：While we were talking, the teacher came in.（我們正在談話時(shí)，老師進(jìn)來(lái)了。）The bus had le