As的用法歸納
as的用法很多，又比較復(fù)雜，本文就此作一歸納：
一、作副詞，意為"相同地"，"同樣地".例如：They don't have as many airplanes. 他們沒有同樣多的飛機(jī)。
二、作連詞，1. 引導(dǎo)時(shí)間狀語從句as與when，while都是引導(dǎo)時(shí)間狀語從句的從屬連詞，含義都是"當(dāng)……的時(shí)候".但它們有區(qū)別：
（1） when作"當(dāng)……的時(shí)候"解，可以指較短的（一點(diǎn)）時(shí)間，也可指一段時(shí)間。從句的動(dòng)作可以與主句的動(dòng)作同時(shí)發(fā)生，也可以先于主句的動(dòng)作發(fā)生。例如：John was having his dinner when I saw him. 當(dāng)我看到約翰的時(shí)候，他正在吃飯。
She can write only when the baby is asleep. 只有嬰兒睡著的時(shí)候，她才能寫作。
（2）while常表示一段較長(zhǎng)的時(shí)間或一個(gè)過程，強(qiáng)調(diào)主句謂語動(dòng)詞與從句謂語動(dòng)詞同時(shí)發(fā)生或在從句動(dòng)作過程中發(fā)生。例如：We must strike while the iron is hot. 要趁熱打鐵。
While we were reading， the teacher came in. 我們正在讀書的時(shí)候，老師走了進(jìn)來。
（3） 但屬下列情形時(shí)，只用as， 而不用when或while.
① 用于表示同一個(gè)人的兩種動(dòng)作交替進(jìn)行，指"一邊……，一邊……".例如：The girl dances as she sings on the stage.那個(gè)女孩在舞臺(tái)邊唱歌邊跳舞。
He looked behind from time to time as he went forward. 當(dāng)他朝前走時(shí)，不時(shí)地向后看。
② 表示兩個(gè)同步發(fā)展的動(dòng)作或行為，譯為"隨著……".例如：As time went on / by， she became more and more worried. 隨著時(shí)間的流逝，她變得越來越焦慮。
As he grew older， he became more intelligent. 隨著他年齡的增長(zhǎng)，他變得更有才智了。
③ 表示兩個(gè)短促行為或事件幾乎同時(shí)發(fā)生。例如：I thought of it just as you opened your mouth. 恰好在你開口時(shí)，我想到了它。
Just as the flying worm hit her face， she gave a loud cry. 恰巧在飛蟲撞到她臉上時(shí)，她大哭起來。
as的用法很多，又比較復(fù)雜，本文就此作一歸納：
一、作副詞，意為"相同地"，"同樣地".例如：They don't have as many airplanes. 他們沒有同樣多的飛機(jī)。
二、作連詞，1. 引導(dǎo)時(shí)間狀語從句as與when，while都是引導(dǎo)時(shí)間狀語從句的從屬連詞，含義都是"當(dāng)……的時(shí)候".但它們有區(qū)別：
（1） when作"當(dāng)……的時(shí)候"解，可以指較短的（一點(diǎn)）時(shí)間，也可指一段時(shí)間。從句的動(dòng)作可以與主句的動(dòng)作同時(shí)發(fā)生，也可以先于主句的動(dòng)作發(fā)生。例如：John was having his dinner when I saw him. 當(dāng)我看到約翰的時(shí)候，他正在吃飯。
She can write only when the baby is asleep. 只有嬰兒睡著的時(shí)候，她才能寫作。
（2）while常表示一段較長(zhǎng)的時(shí)間或一個(gè)過程，強(qiáng)調(diào)主句謂語動(dòng)詞與從句謂語動(dòng)詞同時(shí)發(fā)生或在從句動(dòng)作過程中發(fā)生。例如：We must strike while the iron is hot. 要趁熱打鐵。
While we were reading， the teacher came in. 我們正在讀書的時(shí)候，老師走了進(jìn)來。
（3） 但屬下列情形時(shí)，只用as， 而不用when或while.
① 用于表示同一個(gè)人的兩種動(dòng)作交替進(jìn)行，指"一邊……，一邊……".例如：The girl dances as she sings on the stage.那個(gè)女孩在舞臺(tái)邊唱歌邊跳舞。
He looked behind from time to time as he went forward. 當(dāng)他朝前走時(shí)，不時(shí)地向后看。
② 表示兩個(gè)同步發(fā)展的動(dòng)作或行為，譯為"隨著……".例如：As time went on / by， she became more and more worried. 隨著時(shí)間的流逝，她變得越來越焦慮。
As he grew older， he became more intelligent. 隨著他年齡的增長(zhǎng)，他變得更有才智了。
③ 表示兩個(gè)短促行為或事件幾乎同時(shí)發(fā)生。例如：I thought of it just as you opened your mouth. 恰好在你開口時(shí)，我想到了它。
Just as the flying worm hit her face， she gave a loud cry. 恰巧在飛蟲撞到她臉上時(shí)，她大哭起來。