when和while的區(qū)別及用法3頁

1、 when和while的區(qū)別when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(dǎo)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。when 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。由when引導(dǎo)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(dǎo)，如：

2、a. When the teacher came in, we were talking.當(dāng)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.when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

3、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。拓展：when，while，as引導(dǎo)時間狀語從句的區(qū)別when，while，as顯然都可以引導(dǎo)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？Sorry，I wa

4、s 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。Strike 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(xué)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。When he had finished his homework，he took a

5、short rest（finished先發(fā)生）當(dāng)他完成作業(yè)后，他休息了一會兒。When I got to the airport，the guests had left（got to后發(fā)生）當(dāng)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。When While As we were dancing，a stranger came in（dance為延續(xù)性動詞）當(dāng)我們跳舞時，一位陌生人走了進來。When While As she was making a phone call，I was writing a lette

6、r（make為延續(xù)性動詞）當(dāng)她在打電話時，我正在寫信。3當(dāng)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。As years go by，China is getting stronger and richer隨著時間一年一年過去，中國

7、變得越來越富強了。The little girls sang as they went小姑娘們一邊走，一邊唱。The 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。You shall borrow the book when I have finished reading it在我讀完這本書后，你可以借閱。When the manager comes here for a visit next week，Ill talk with him

8、 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）。sbhad hardly（scarcely） done sthwhenHardly Scarcely had sbdone sthwhenI had hardly scarcely closed my eyes when someone knocked at the doorHardly 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。I had hardly scarcel

9、y entered my room when the telephone rangHardly Scarcely had I entered my room when the telephone rang我剛一走進房門，電話就響了。 終止性動詞英語中，動詞按其動作發(fā)生的方式、動作發(fā)生過程的長短，可分為延續(xù)性動詞和終止性動詞。終止性動詞也稱非延續(xù)性動詞、瞬間動詞或短暫性動詞，表示不能延續(xù)的動作，這種動作發(fā)生后立即結(jié)束。如open, close, finish, begin, come, go, arrive, reach, get to, leave, move, borrow,buy等 延續(xù)性動詞延續(xù)性動詞表示能夠延續(xù)的動作，這種動作可以延續(xù)下去或產(chǎn)生持久影響。如：learn, work, stand, lie, know, walk, keep, have, wait, watch, sing, read, sleep, live, stay等。延續(xù)性動詞表示的動作不但可以延續(xù)，而且可以產(chǎn)生持久的影響。常見的這