2020考研英語(yǔ)常用詞匯之：as的用法

　　六月份了，暑期將至，考研英語(yǔ)復(fù)習(xí)首先對(duì)于基礎(chǔ)常識(shí)要有了解，復(fù)習(xí)之初最好把這些都搞明白，然后有針對(duì)性的開展復(fù)習(xí)，英語(yǔ)復(fù)習(xí)必然從背單詞開始。下面分享了考研英語(yǔ)常用詞匯：as的用法總結(jié)，希望對(duì)大家有所幫助。

　　一、as作為介詞的用法：

　　1.表示“作為”，“以……身份”。例如：Tom found a job as a teacher.

　　2.表示“像…一樣”，例如：They were all dressed as policeman.

　　二、as作為副詞的用法：

　　1.表示“與…等同”。如：They don’t have as many boxes.

　　2.表示“像，如”。如：As before, he remained slient.

　　三、as可作從屬連詞，作關(guān)系副詞時(shí)可以引導(dǎo)比較、時(shí)間、原因及方式等四種狀語(yǔ)從句，作關(guān)系代詞時(shí)可以引導(dǎo)定語(yǔ)從句：

　　(一)as作從屬連詞引導(dǎo)狀語(yǔ)從句時(shí)：

　　1.表示“在…期間，當(dāng)…的時(shí)候”引導(dǎo)時(shí)間狀語(yǔ)從句，要注意其與when、while的用法區(qū)別。as與when，while都是引導(dǎo)時(shí)間狀語(yǔ)從句的從屬連詞，含義都是“當(dāng)……的時(shí)候”。但它們有區(qū)別：用when時(shí)，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;用while時(shí)，從句的動(dòng)作為一過(guò)程，主句動(dòng)作與從句動(dòng)作同時(shí)進(jìn)行或在從句動(dòng)作過(guò)程中發(fā)生;用as時(shí)，主句和從句的動(dòng)作同時(shí)發(fā)生，具有延續(xù)的含義。

　　下列情形時(shí),只用as，而不用when或while。

　　1)表示兩個(gè)同步發(fā)生的動(dòng)作或行為，意思是“隨著…的發(fā)展”。如：

　　As time went on, she became more and more worried.

　　As we get older, we become more and more interested in everything.

　　2)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”。如：

　　The girl sings as she goes to supermarket.

　　He looked behind occasionally as he went forward in the forest.

　　3)接在名詞后面表示某一個(gè)年齡段時(shí)。如：

　　As a young man, he was active in answering questions.

　　4)表示兩個(gè)短暫行為或事情幾乎同時(shí)發(fā)生。如：

　　I watched her as she read the book.

　　I thought of it just as you opened your mouth.

　　when作“當(dāng)……的時(shí)候”解,可以指較短的時(shí)間，也可指一段時(shí)間。如：

　　It was raining when he arrived at the factory.

　　When I was at college, I could speak several foreign languages.

　　while常表示一段較長(zhǎng)的時(shí)間或一個(gè)過(guò)程,強(qiáng)調(diào)主句謂語(yǔ)動(dòng)詞與從句謂語(yǔ)動(dòng)詞同時(shí)發(fā)生。如：He was watching TV while his mother was cooking.

　　2.as作“既然”、“由于”解，引導(dǎo)原因狀語(yǔ)從句，常用來(lái)表示已為人們所知或顯而易見的原因或理由。與because，since相比，as一般放在句首，語(yǔ)氣較弱，較口語(yǔ)化。如：

　　As you’re not feeling well, you may stay at home.

　　As he wasn’t ready, we went without him.

　　3.as作“像”、“按照……的方式”解，引導(dǎo)方式狀語(yǔ)從句。如：

　　Leave things as they are.

　　Remember, you must do everything as I do.

　　4.表示“雖然，盡管”，引導(dǎo)讓步狀語(yǔ)從句，多在主句之前，且常用倒裝語(yǔ)序，模式為：adj. /adv. /n. /v.+as+主語(yǔ)+謂語(yǔ)+主句。如：

　　Young as he is, he knows much about electricity.

　　Try as he did, he failed again.

　　知識(shí)拓展：用于as…as或not / so/ as…as中，前一個(gè)as是副詞，后一個(gè)as是連詞，引導(dǎo)比較狀語(yǔ)從句。如：

　　They help the old as much as they can.

　　I don’t speak English as well as she does.

　　(二)as作從屬連詞引導(dǎo)定語(yǔ)從句時(shí)，表示“正如”：

　　1.引導(dǎo)限制性定語(yǔ)從句。如：

　　He isn’t the same person as he used to be.

　　I have never heard such story as he is telling.

　　I am not so strong a man as I was.

　　2.引導(dǎo)非限制性定語(yǔ)從句，修飾整個(gè)主句或主句的一部分，可在句首、句中、句末。如：He is very careful, as we all know.

　　As is well known, she has two sisters.

　　This machine, as might be expected, has stopped operating.

　　總之，通過(guò)以上的分析，我們對(duì)as的詞性和用法有了比較全面的理解和把握，這樣才能在實(shí)際的運(yùn)用中做到心中有數(shù)，應(yīng)付自如。