小Q科普第一波:when還是while 傻傻分不清楚

when 和while的用法區(qū)別

①when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。

②when 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(qiáng)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。

③由when引導(dǎo)的時間狀語從句,主句用過去進(jìn)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(jìn)行時的時候,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,則為: While we were talking, the teacher came in.

b. They were singing while we were dancing.

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。?

【擴(kuò)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。

①Why do you want a new job when you've 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?

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(xù)性動詞,表示一種持續(xù)的狀態(tài))趁熱打鐵。

④The 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。

①When 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。

①When /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(jìn)來。

②When /While /As she was making a phonecall,I was writing a letter.(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(jìn)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。

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

②The 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(qiáng)了。

④The little girls sang as they went?