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高考學考
when，while，as引導時間狀語從句的區別
作者：admin
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發布時間：
2005-10-18
點擊數：11116
when，while，as引導時間狀語從句的區別
when，while，as顯然都可以引導時間狀語從句，但用法區別非常大。
一、when可以和延續性動詞連用，也可以和短暫性動詞連用；而while和as隻能和延續性動詞連用。
① Why do you want a new job when youve got such a good one already？（get為短暫性動詞）你已經找到如此好的工作，為何還想再找新的？
②Sorry，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為延續性動詞，表示一種持續的狀態）趁熱打鐵。
④ The students took notes as they listened．（listen為延續性動詞）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、之後或同時發生；while和as從句的謂語動作必須是和主句謂語動作同時發生。
1．從句動作在主句動作前發生，隻用 when。
①When he had finished his homework，he took a short rest．（finished先發生）當他完成作業後，他休息了一會兒。
②When I got to the airport，the guests had left．（got to後發生）當我趕到飛機場時，客人們已經離開了。
2．從句動作和主句動作同時發生，且從句動作為延續性動詞時，when，while，as都可使用。
①When ／While ／As we were dancing，a stranger came in．（dance為延續性動詞）當我們跳舞時，一位陌生人走了進來。
②When ／While ／As she was making a phonescall，I was writing a letter．（make為延續性動詞）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生的背景或條件時，隻能用 as。這時，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。
④The little girls sang as they went．小姑娘們一邊走，一邊唱。
⑤The 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．在我讀完這本書後，你可以借閱。
②When the manager comes here for a visit next week，Ill talk with him about this．下周，經理來這參觀時，我會和他談談此事。
三、when用於表示“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．．．
①I 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。
②I had hardly ／scarcely entered my room when the telephones rang．＝Hardly ／Scarcely had I entered my room when the telephones rang．我剛一走進房門，電話就響了。