prep(1)像，如……一樣(like;so as to appear to be)：dress/disguise sb～an officer把某人打扮/偽裝成軍官;die～a hero像英雄一樣死去;talk～an old friend如老朋友一樣談話;rise～one man一個(gè)人一樣站立起來(lái);unite～one family團(tuán)結(jié)如一家人;
?(2)作為，當(dāng)作，以……的身份(in the state，character，function，condition，job，etc of being)：work/serve/act～a lawyer當(dāng)/當(dāng)/充當(dāng)律師;speak～a spokesman以發(fā)言人身份談話;be famous/known～an eloquent orator作為雄辯的演說(shuō)家而著名/聞名;a job/post～a manager 經(jīng)理的工作/職位;treat/regard/accept/look on sb～a friend把某人當(dāng)朋友對(duì)待/視為朋友/看作朋友/視為朋友;describe sth～a victory把……描繪成勝利;take/use sth～an example把……當(dāng)作/用作例子;regard/think of sb～(being)happy認(rèn)為/覺(jué)得某人幸福;look upon sth～very advanced把……視為非常先進(jìn);see sth～changing把……看作是不斷變化的;
?(3)作為，由于是(since sb is sth)：A～a doctor/a scientist/her son/his secretary，I should... 作為大夫/科學(xué)家/她的兒子/他的秘書(shū)，我應(yīng)該……
?(4)作為，當(dāng)……的時(shí)候(when or while sb is sth)：A～a child/a school girl/a young woman，she showed every sign of genius.她年幼/是中學(xué)生/年輕的時(shí)候，充分顯示出了天才的跡象。I used to eat a lot～a child but～an adult I eat little.我小時(shí)候吃得很多，可成人后吃得很少。
?(5)以……的形式(in the form of)：A loaf goes into the oven～dough.面包放進(jìn)烤爐時(shí)是面團(tuán)。We all start life～babies.我們來(lái)到世上時(shí)都是嬰兒。
?adv(1)和(像)……一樣(to the same degree or amount...as;equally...with)(用于adj或adv前，構(gòu)成表示比較的as...as 結(jié)構(gòu))：1)(第二個(gè)as為連詞)：run (twice/half/just/nearly)～fast as possible/as one can/as sb does/as one wants to 跑得盡可能/盡可能/和某人/與其愿望(的兩倍/一半/正好/差不多)那么快;be(seem to be/look)(twice/...)～clever as one sounded on the phone/as one looks in the film/as before(似乎/顯得)像電話里的聲音所顯得的/電影里的樣子/從前(兩倍/……)那樣機(jī)靈;be～good an actress as one is a singer演技和唱歌水平一樣好;be～eloquent a speaker as one's father is是一個(gè)和其父一樣雄辯的演說(shuō)家;need(get)(twice/...)～much money as one expected/as possible 需要(弄到)所希望/可能的(兩倍/……)那么多的錢(qián);catch (twice/...)～many(much) as one wants/as one can抓到想要/所能抓的(兩倍/……)那么多;2)(第二個(gè)as為介詞)：work(twice/...)～hard as they (or them)/as the other people干得有他們/別人(兩倍/……)那么努力;walk(twice/...)～far as that走得有那(兩倍/……)那么遠(yuǎn);be(seem to be/look)(twice/...)～beautiful as that/as she(or her)/as one's sister(似乎/顯得)如那樣/她/其妹妹(兩倍/……)那么漂亮;～brave as a lion/heavy as lead/loud as thunder/silent as the grave 雄獅般勇敢/鉛一般重/如雷灌耳/死一般寂靜;3)(第二個(gè)as引導(dǎo)的部分可省略)：Jack swims fast，but I swim just～fast.杰克游得很快，我也游得同樣快。You have qualities that are just～important.你具有一些同樣很重要的品質(zhì)。She has a lot of money，but he has/hasn't～much.她有許多錢(qián)，他也有/沒(méi)有那么多的錢(qián)。
?(2)如同，像(not differently from;like)：A～before he remained unmoved. 一如既往，他一動(dòng)不動(dòng)。The “b” is silent～in “climb”.這個(gè)b如同在climb中一樣不發(fā)音。
?(3)例如(for example;such as;like)：Some flowers，～the rose，require special care.有些花，例如玫瑰，需要倍加精心。
?conj (1)當(dāng)……的時(shí)候(at the time that;while)：A～he walked/was walking along he met an old friend.他正走著的時(shí)候，突然遇見(jiàn)了一個(gè)朋友。I watched her～she combed her hair.她梳頭時(shí)，我注視著她。She closed her eyes～she uttered the words.她說(shuō)這話時(shí)閉上了眼睛。
?(2)因?yàn)?，由于，既?because;since;for the reason that)(通常位于句首，語(yǔ)義不如because 和since強(qiáng))：A～he was obviously ill，we called the doctor.由于他顯然是病了，我們就叫了大夫。A～you are tired，you had better rest.既然你累了，就最好休息一下。He couldn't come～he had another appointment.他來(lái)不了啦，因?yàn)樗碛屑s會(huì)。
?(3)雖然，盡管(although;regardless of the degree to which)(置于句首的形容詞或副詞之后)：Rich～(或though) he is，he is not happy.盡管他有錢(qián)，但并不幸福。Much～(或though) I want to，I cannot go.雖然我很想去，卻去不了。Try～you will，you won't manage it.無(wú)論你怎么努力，你也對(duì)付不了。
?(4)按(依)照;像，如(in the same way or manner in which)：Do～I(xiàn) say/I told you to/you are told/I do.照我說(shuō)的/我告訴你的/告訴你的/我這樣做。He doesn't speak/think/work～other people do.他說(shuō)話/考慮問(wèn)題/工作和別人不一樣。Leave the room～it is.讓房間保持原來(lái)的樣子。
?(5)(引導(dǎo)關(guān)系從句)1)(用于same...as句式中)：I got the same grade～(或that)you (got).我得了和你一樣的分?jǐn)?shù)。We drove out by the same road～we had entered by.我們的車從來(lái)時(shí)走的那條路開(kāi)了出去。My stand on this is just the same～it was before/four years ago.我在這件事情上的立場(chǎng)和以前/四年前的一樣。2)(用于such...as句式中)：Such women～knew Tom thought he was charming.認(rèn)識(shí)湯姆的女人都認(rèn)為他有魅力。He is not such a fool～he looks.他并不像看上去那么傻。I never heard such stories～he tells.我從未聽(tīng)過(guò)他講的那種故事。3)也是，同樣(and so too)(通常后接be或do+主語(yǔ))：David is tall，～are my brothers.大衛(wèi)個(gè)子高，我的幾個(gè)兄弟也個(gè)子高。Mary is old，～is her husband.瑪麗老了，她丈夫也老了。Jack is a teacher，～was his wife before she had children.杰克是教師，他妻子有孩子以前也是教師。
?(6)按照……(in accordance with what)：Norway，～described in this advertisement，seems to be a wonderful place for a holiday.根據(jù)這則廣告所描述，挪威似乎是個(gè)度假的好地方。Cyprus，～we all know，is an island in the Mediterranean.塞浦路斯，眾所周知，是地中海的一個(gè)島嶼。He is a teacher，～is clear from his manner.從他的舉止可以清楚看出，他是教師。
?(7)猶如，如同(what;in the way that)(表示比例或關(guān)系)：2 is to 8～4 is to 16.2比8就如同4比16。A～some are rich，(so) others are poor. 既有富人，就有窮人。
?as against 而 …… 則……(表示對(duì)比)：The money earned this week amounts to ￡100～against ￡80 last week.本周賺了100英鎊，而上周則是80英鎊。
?as for 至于：A～for going back，that is quite out of the question.至于回去，那是根本不可能的。
?as from，(esp AmE) as of 自(某日)起：A～from/of today you are in charge.從今天起你負(fù)責(zé)。
?as it is 事實(shí)上：I would have liked to have finished by May，but～it is， that is impossible.我本想5月前完成的，實(shí)際上那是不可能了。
?as it were 可以說(shuō)：He is，～it were，a walking dictionary.他可以說(shuō)是一本活字典。
?as to/regards 至于：A～to(doing)that，I haven't decided yet.至于做那件事，我還沒(méi)有決定。He said nothing～regards whether he would come back.至于是否回來(lái)，他什么也沒(méi)說(shuō)。
?as yet 至今尚未：The danger was～yet not serious.危險(xiǎn)還不嚴(yán)重。
?as if /though 似乎，好像：You look～if/though you had seen a ghost.你的樣子就好像見(jiàn)了鬼一樣。He talks～if/though he knew everything.他說(shuō)話的神氣就好像他什么都知道似的。He raised his hand～if to command silence.他舉起一只手好像要命令大家安靜下來(lái)。
?【用法】adv(1)的用法(as...as)多為肯定式;也可以為否定式，不過(guò)，有人堅(jiān)持認(rèn)為此時(shí)副詞(第一個(gè))as應(yīng)改為so為好，如(注意not的位置)：He won't leave as/so soon as she will/as she (or her).(他不會(huì)像她那么快離開(kāi)的。)It's not nearly as/so cold as it was yesterday/that.(今天不大像昨天/那樣那么冷。)
?【辨異】 1)as與like2 都可用作介詞，但此時(shí)as的本義為 in the role of(以……的身份)，如：die as a hero(死得是個(gè)英雄——就是英雄);like則意為“像”，如：die like a hero(死得像個(gè)英雄——指表現(xiàn)像英雄);as還可用作連詞(后接從句或介詞短語(yǔ));而like 則不可(其后僅可接名詞短語(yǔ))，如：die as a hero does(像英雄那樣(英勇)就義)，又如：Do it like me/Do it as I (do).(像我一樣做。)但是，在非正式英語(yǔ)中，like也可用作連詞，代替as(以及as if)(不過(guò)這種用法一般認(rèn)為應(yīng)避免)，如：It happened as/like you said it would.(事情正如你所說(shuō)的那樣發(fā)生了。)He acted as if /like he was afraid to go home.(他那樣子就好像他害怕回家似的。)2)as，because與since和for都表示原因。because表示直接的原因，語(yǔ)氣最強(qiáng)，可用來(lái)回答 why 的問(wèn)題(其他幾個(gè)皆不可)，如：I was sleeping because I was tired. as和since則表示附帶的原因，經(jīng)常置于句首，如：As/Since I was tired，I was sleeping.for較as和since正式，表示一個(gè)事后想起的原因，對(duì)前一句所陳述的事實(shí)進(jìn)行補(bǔ)充說(shuō)明，與前一句為并列關(guān)系，如：I was sleeping，for I was tired.