1．when，while，as 三者均可譯爲(wèi)“在……時(shí)候”。when引導(dǎo)的從句，動(dòng)詞既可以是延續(xù)性的，也可以是終止性的。一般來(lái)說(shuō)，儅主句的動(dòng)作正在進(jìn)行時(shí)，when引導(dǎo)的從句的動(dòng)作才發(fā)生；while引導(dǎo)的從句中，動(dòng)詞衹能是延續(xù)性的，一般來(lái)說(shuō)，儅while引導(dǎo)的從句的動(dòng)作正在進(jìn)行時(shí)，主句的動(dòng)作才發(fā)生；as表示隨著短暫動(dòng)作的發(fā)生，另一行爲(wèi)伴隨發(fā)生。 He was riding to school when he was hit by a car this morning. 儅他被一輛小汽車撞到的時(shí)候他正騎車上學(xué)。 You'd better turn off the water while you brush your teeth. 儅你刷牙的時(shí)候你最好關(guān)掉水。 She sang as she walked. 她一邊走一邊唱歌。 2．so…that…，such…that… 從句＋形容詞/副詞＋that從句； so＋形容詞＋a/an＋可數(shù)名詞的單數(shù)＋that從句； so＋many/much/few/little＋名詞＋that從句； such＋a/an＋形容詞＋可數(shù)名詞單數(shù)＋that從句； such＋形容詞＋不可數(shù)名詞/可數(shù)名詞複數(shù)＋that從句。 Hangzhou is so beautiful a city that lots of visitors come here every year. 杭州如此美以至於每年許多遊客來(lái)這。 She is such a good girl that we all like her. 她是如此好的一個(gè)女孩，以至於我們大家都喜歡她。 There are so many students on the playground. 操場(chǎng)上有如此多的學(xué)生。