when和while的區(qū)別用法

　　when和while的區(qū)別

　?、賥hen是at or during the time that, 既指時(shí)間點(diǎn),也可指一段時(shí)間;

　　while是during the time that,只指一段時(shí)間,因此when引導(dǎo)的時(shí)間狀語(yǔ)從句中的動(dòng)詞可以是終止性動(dòng)詞,也可以是延續(xù)性動(dòng)詞,而while從句中的動(dòng)詞必須是延續(xù)性動(dòng)詞.

　?、谟蓋hen引導(dǎo)的時(shí)間狀語(yǔ)從句,主句用過(guò)去進(jìn)行時(shí),從句應(yīng)用一般過(guò)去時(shí);如果從句和主句的動(dòng)作同時(shí)發(fā)生,兩句都用過(guò)去進(jìn)行時(shí)的時(shí)候,多用while引導(dǎo),如：

　　a. When the teacher came in, we were talking.

　　當(dāng)此句改變主從句的位置時(shí),則為：

　　While we were talking, the teacher came in.

　　b. They were singing while we were dancing.

　?、踳hen 說(shuō)明從句的動(dòng)作和主句的動(dòng)作可以是同時(shí),也可以是先后發(fā)生;while 則強(qiáng)調(diào)主句的動(dòng)作在從句動(dòng)作的發(fā)生的過(guò)程中或主從句兩個(gè)動(dòng)作同時(shí)發(fā)生.

　　④when和while 還可作并列連詞.when表示“在那時(shí)”;while表示“而,卻”,表對(duì)照關(guān)系.如：

　　a. The children were running to move the bag of rice when they heard the sound of a motor bike.

　　孩子們正要跑過(guò)去搬開(kāi)那袋米,這時(shí)他們聽(tīng)到了摩托車的聲音.

　　b. He is strong while his brother is weak.

　　他長(zhǎng)得很結(jié)實(shí),而他弟弟卻很瘦弱.

　　具體你可以參考這一段.

　　when,while,as引導(dǎo)時(shí)間狀語(yǔ)從句的區(qū)別

　　when,while,as顯然都可以引導(dǎo)時(shí)間狀語(yǔ)從句,但用法區(qū)別非常大.

　　一、when可以和延續(xù)性動(dòng)詞連用,也可以和短暫性動(dòng)詞連用;而while和as只能和延續(xù)性動(dòng)詞連用.

　?、?Why do you want a new job when youve got such a good one already?(get為短暫性動(dòng)詞)你已經(jīng)找到如此好的工作,為何還想再找新的?

　?、赟orry,I was out when you called me.(call為短暫性動(dòng)詞)對(duì)不起,你打電話時(shí)我剛好外出了.

　　③Strike while the iron is hot.(is為延續(xù)性動(dòng)詞,表示一種持續(xù)的狀態(tài))趁熱打鐵.

　?、?The students took notes as they listened.(listen為延續(xù)性動(dòng)詞)學(xué)生們邊聽(tīng)課邊做筆記.

　　二、when從句的謂語(yǔ)動(dòng)詞可以在主句謂語(yǔ)動(dòng)作之前、之后或同時(shí)發(fā)生;while和as從句的謂語(yǔ)動(dòng)作必須是和主句謂語(yǔ)動(dòng)作同時(shí)發(fā)生.

　　1.從句動(dòng)作在主句動(dòng)作前發(fā)生,只用 when.

　?、賅hen he had finished his homework,he took a short rest.(finished先發(fā)生)當(dāng)他完成作業(yè)后,他休息了一會(huì)兒.

　　②When I got to the airport,the guests had left.(got to后發(fā)生)當(dāng)我趕到飛機(jī)場(chǎng)時(shí),客人們已經(jīng)離開(kāi)了.

　　2.從句動(dòng)作和主句動(dòng)作同時(shí)發(fā)生,且從句動(dòng)作為延續(xù)性動(dòng)詞時(shí),when,while,as都可使用.

　　①When /While /As we were dancing,a stranger came in.(dance為延續(xù)性動(dòng)詞)當(dāng)我們跳舞時(shí),一位陌生人走了進(jìn)來(lái).

　　②When /While /As she was making a phonecall,I was writing a letter.(make為延續(xù)性動(dòng)詞)當(dāng)她在打電話時(shí),我正在寫(xiě)信.

　　3.當(dāng)主句、從句動(dòng)作同時(shí)進(jìn)行,從句動(dòng)作的時(shí)間概念淡化,而主要表示主句動(dòng)作發(fā)生的背景或條件時(shí),只能用 as.這時(shí),as常表示“隨著……”;“一邊……,一邊……”之意.

　　① As the time went on,the weather got worse.(as表示“隨著……”之意)

　　② The atmosphere gets thinner and thinner as the height increases.隨著高度的增加,大氣越來(lái)越稀薄.

　?、跘s years go by,China is getting stronger and richer.隨著時(shí)間一年一年過(guò)去,中國(guó)變得越來(lái)越富強(qiáng)了.

　　④The little girls sang as they went.小姑娘們一邊走,一邊唱.

　?、軹he sad mother sat on the roadside,shouting as she was crying.傷心的媽媽坐在路邊,邊哭邊叫.

　　4.在將來(lái)時(shí)從句中,常用when,且從句須用一般時(shí)代替將來(lái)時(shí).

　　①You shall borrow the book when I have finished reading it.在我讀完這本書(shū)后,你可以借閱.

　　②When the manager comes here for a visit next week,Ill talk with him about this.下周,經(jīng)理來(lái)這參觀時(shí),我會(huì)和他談?wù)劥耸?

　　三、when用于表示“一……就……”的句型中(指過(guò)去的事情).

　　sb.had hardly(=scarcely) done sth.when...=Hardly / Scarcely had sb.done sth.when...

　?、買(mǎi) had hardly /scarcely closed my eyes when someone knocked at the door.=Hardly / Scarcely had I closed my eyes when someone knocked at the door.我剛一閉上眼,就有人在敲門(mén)了.

　　②I had hardly /scarcely entered my room when the telephone rang.=Hardly /Scarcely had I entered my room when the telephone rang.我剛一走進(jìn)房門(mén),電話就響了.