轉(zhuǎn)：as可用作連詞,引導(dǎo)比較、時(shí)間、原因及方式等四種狀語(yǔ)從句,應(yīng)注意的是,引導(dǎo)的比較狀語(yǔ)從句往往有省略；引導(dǎo)的時(shí)間狀語(yǔ)從句一般用一般現(xiàn)在時(shí)而不用一般將來(lái)時(shí)；引導(dǎo)原因狀語(yǔ)從句時(shí)與“Because”和“since”引導(dǎo)的從句比較起起來(lái)語(yǔ)氣最弱.
as作介詞,意思時(shí)“作為”,“以……身份”.例如：He came to China as a tourist five years ago.
而表示像…一樣時(shí),like通常作介詞用,而介詞后面通常接名詞,代名詞和動(dòng)名詞.
as in Australia“和在澳大利亞一樣”.
as……as
AS +adj(原級(jí))+AS
AS +adv(原級(jí))+AS
as soon as 一……就
as soon as possible 盡可能快地
as early as possible 盡可能早的
as carefully as you can 盡可能認(rèn)真地
as careful as you can 盡可能認(rèn)真的
1.as是連詞,表示“隨著”的意義.lives是life的復(fù)數(shù),意義是“生活”.

2.as是連詞,表示“因?yàn)?由于”的意義.wanting是現(xiàn)在分詞,表示主動(dòng)意義,wanting to buy cars=who want to buy cars.
As的用法小結(jié)
as可以作連詞、介詞及關(guān)系代詞和副詞.現(xiàn)將其用法小結(jié)如下:
（一）、 as作連詞的用法:
1.作“在-------期間,當(dāng)----的時(shí)候”引導(dǎo)時(shí)間狀語(yǔ)從句.注意與when、 while的用法區(qū)別.
①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.如:
The girl sings as she goes to school.
He looked behind occasionally as he went forward in the forest.
2)表示兩個(gè)同步發(fā)生的動(dòng)作或行?意思是隨著-----的發(fā)展.如:
As time went on / by,she became more and more beautiful .
As children get older,they become more and more interested in everything.
3)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.
Just as the flying worm hit her face,she gave a loud cry.
4)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 sports.
②when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.如:When I was at college,I could speak several foreign languages.When the clock struck twelve,I had slept for 2hours.
③ 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:Work while you work.Play while you play.
2.As =Since 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(jiàn)的原因或理由.如:As he’s been ill for ages,I will help him.
As / Since you're not feeling well,you may stay at home.
As he wasn't ready ,we went without him.
3.As =in the way that作"像"、"按照……的方式"解,引導(dǎo)方式狀語(yǔ)從句.如:
Do as I told you.
Remember,you must do everything as I do.
4.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 helped the old as much as possible.
I don't speak English so/ as well as she does.
5.表示雖然,盡管 等,引導(dǎo)讓步狀語(yǔ)從句,常用倒裝語(yǔ)序,模式為:
adj./adv./ n.+as +主語(yǔ)+謂語(yǔ)+主句.如:Young as he is,he knows much.
Tired as they were,they walked on.
6.表示也------一樣.She is a doctor,as was her husband.
（二）、 as作關(guān)系代詞,引導(dǎo)定語(yǔ)從句,表示正如,這一點(diǎn).如:
He is very careful,as we all know.
As is well-known,Taiwan belongs to China.
另外,當(dāng)先行詞被the same,such等詞修飾時(shí),常用as來(lái)引導(dǎo)定語(yǔ)從句.如:
Such a clever girl as she can learn anything quickly.
I was reading the same book as he bought yesterday.
（三）、as作介詞的用法.
1.表示好像.如:He dressed as a policeman.
2.表示作為當(dāng)作.如：I found a job as a guide.
3.當(dāng)某人是某身份時(shí).如：As a child ,she was sent to abroad.
4.as引導(dǎo)的介詞短語(yǔ)大多用作狀語(yǔ),as譯為"作為";少數(shù)情況可引起賓語(yǔ)補(bǔ)足語(yǔ).如:
As a Party member,I'll take the lead in everything.(狀語(yǔ))
She works as a model.(狀語(yǔ))
She has me as one of her best friends.(引起賓語(yǔ)補(bǔ)足語(yǔ))
（四）、作副詞的用法 1 表示與------等同.如：This dress is twice as expensive as that one.2 像,如等.如：As before,he remained unmoved.
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,才能在實(shí)際的運(yùn)用中做到心中有數(shù),應(yīng)付裕如.