when連接兩個(gè)持續(xù)動(dòng)作或瞬間動(dòng)作,while只連持續(xù)動(dòng)作，只用while的情況有兩種：1、while后面引導(dǎo)持續(xù)性動(dòng)作，表示正在進(jìn)行，這時(shí)不用when。2、while 表示對(duì)比，不用when 例:she likes playing football,while i likes playing basketball.。

when 和while的用法區(qū)別 

①when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。 ②when 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。 ③由when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. 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)去搬開那袋米，這時(shí)他們聽到了摩托車的聲音。 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。