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, 既指時間點,也可指一段時間;

　　while是during the time that,只指一段時間,因此when引導的時間狀語從句中的動詞可以是終止性動詞,也可以是延續(xù)性動詞,而while從句中的動詞必須是延續(xù)性動詞.

　　②由when引導的時間狀語從句,主句用過去進行時,從句應(yīng)用一般過去時;如果從句和主句的動作同時發(fā)生,兩句都用過去進行時的時候,多用while引導,如：

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

　　當此句改變主從句的位置時,則為：

　　While we were talking, the teacher came in.

　　b. They were singing while we were dancing.

　?、踳hen 說明從句的動作和主句的動作可以是同時,也可以是先后發(fā)生;while 則強調(diào)主句的動作在從句動作的發(fā)生的過程中或主從句兩個動作同時發(fā)生.

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

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

　　孩子們正要跑過去搬開那袋米,這時他們聽到了摩托車的聲音.

　　b. He is strong while his brother is weak.

　　他長得很結(jié)實,而他弟弟卻很瘦弱.

　　具體你可以參考這一段.

　　when,while,as引導時間狀語從句的區(qū)別

　　when,while,as顯然都可以引導時間狀語從句,但用法區(qū)別非常大.

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

　?、?Why do you want a new job when youve got such a good one already?(get為短暫性動詞)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為短暫性動詞)對不起,你打電話時我剛好外出了.

　　③Strike while the iron is hot.(is為延續(xù)性動詞,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)性動詞)學生們邊聽課邊做筆記.

　　二、when從句的謂語動詞可以在主句謂語動作之前、之后或同時發(fā)生;while和as從句的謂語動作必須是和主句謂語動作同時發(fā)生.

　　1.從句動作在主句動作前發(fā)生,只用 when.

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

　?、赪hen I got to the airport,the guests had left.(got to后發(fā)生)當我趕到飛機場時,客人們已經(jīng)離開了.

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

　?、賅hen /While /As we were dancing,a stranger came in.(dance為延續(xù)性動詞)當我們跳舞時,一位陌生人走了進來.

　?、赪hen /While /As she was making a phonecall,I was writing a letter.(make為延續(xù)性動詞)當她在打電話時,我正在寫信.

　　3.當主句、從句動作同時進行,從句動作的時間概念淡化,而主要表示主句動作發(fā)生的背景或條件時,只能用 as.這時,as常表示“隨著……”;“一邊……,一邊……”之意.

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

　?、?The atmosphere gets thinner and thinner as the height increases.隨著高度的增加,大氣越來越稀薄.

　　③As years go by,China is getting stronger and richer.隨著時間一年一年過去,中國變得越來越富強了.

　?、躎he 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.在將來時從句中,常用when,且從句須用一般時代替將來時.

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

　?、赪hen the manager comes here for a visit next week,Ill talk with him about this.下周,經(jīng)理來這參觀時,我會和他談?wù)劥耸?

　　三、when用于表示“一……就……”的句型中(指過去的事情).

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

　?、買 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,就有人在敲門了.

　?、贗 had hardly /scarcely entered my room when the telephone rang.=Hardly /Scarcely had I entered my room when the telephone rang.我剛一走進房門,電話就響了.