as的用法
as是我們英語學習中經常會碰到的詞。以下是小編帶來的as的用法，希望對你有幫助。
一、as作連詞的用法
1. as...as的用法
as...as意為"和……一樣"，表示同級的比較。使用時要注意第一個as為副詞，第二個as為連詞。其基本結構為：as+ adj./ adv. +as。例如：
(1)This film is as interesting as that one.這部電影和那部電影一樣有趣。
(2)Your pen writes as smoothly as mine.你的鋼筆書寫起來和我的一樣流暢。
其否定式為not as/so +adj./ adv. +as。例如：
This dictionary is not as/so useful as you think.這本字典不如你想象的'那樣有用。
若有修飾成分，如twice, three times, half, a quarter等，則須置于第一個as之前。例如：
Your bag is twice as expensive as mine.你的袋子比我的貴一倍。
幾個關于as...as的常見句型：
(1)as...as possible
Please answer my question as soon as possible.請盡快回答我的問題。
(2)as...as usual/before
She looks as pretty as before.她看起來和以前一樣漂亮。
(3)as long as... (引導條件狀語從句)
It took us as long as three years to carry out the plan.我們花了長達三年的時間才完成這項計劃。
(4)as far as
He walked as far as the railway station yesterday evening.昨天傍晚，他一直散步到火車站。
(5)as well as
She cooks as well as her mother does.她燒菜燒得跟她母親一樣好。
一些帶有as...as結構的常見短語歸納：
as busy as a bee像蜜蜂一樣忙碌
as easy as ABC像ABC一樣容易
as deep as a well像井一樣深
as light as a feather像羽毛一樣輕
as soft as butter像黃油一樣軟
as rich as a Jew像猶太人一樣富裕
2. as用作連詞引導時間狀語從句
as與when，while都是引導時間狀語從句的從屬連詞，含義都是"當……的時候"。但它們有區別：用when時，從句的動作可以與主句的動作同時發生，也可以先于主句的動作發生;用while時，從句的動作為一過程，主句動作與從句動作同時進行或在從句動作過程中發生;用as時，主句和從句的動作同時發生，具有延續的含義。例如：
(1)It was snowing when he arrived at the construction site.他到達工地時，天正在下雪。
(2)He was watching TV while his mother was cooking.他母親做飯時他在看電視。
(3) You will grow wiser as you grow older.你會隨著年齡的增長而越來越聰明。
3. as用作連詞引導原因狀語從句
as，because，since都可以表示因果關系，連接原因狀語從句，含義是"因為，由于"，但它們有區別：because表示的語氣最強;as一般放在句首，語氣較弱，較口語化;since常常用在書面語中，表示多為對方已知的、或稍加分析便可得知的原因，有時可譯作"既然"。例如：
(1) He will succeed because he is in earnest.他一定會成功，因為他很認真。
(2) Since you are so sure of it he”ll believe you.既然你對此如此有把握，他會相信你的。
(3) As rain has fallen, the air is cooler.因為下過雨，空氣比較清爽。
4. as作連詞引導讓步狀語從句
as與although (或though)，however (或no matter how)等都可以引導讓步狀語從句，含義是"雖然，盡管"，但它們有區別：although語氣稍正式些，可放在句首，也可放在句中，主句中不能再用but，但可以用yet;as所表示的語氣較強，引導的讓步狀語從句用倒裝語序;however引導讓步狀語從句時，它的后面可跟形容詞或副詞，也要用倒裝語序。例如：
(1) Although he is quite old, he still jogs every day.他雖然年紀相當大，仍然每天慢跑。
(2) Strange as it may seem, nobody was injured in the accident.這次意外雖然顯得令人不可思議，卻沒有人受傷。
(3) However hard he may try, he will not attain his goal.無論他怎樣努力也達不到目標。
二、as作關系代詞的用法
關系代詞as引導定語從句時，既可以單獨使用，也可以與其他詞連用，其用法要比that和which更為復雜。
1. as引導定語從句與其他詞連用
①用于the same...as結構中
This is the same book as I read last week.這本書和我上周讀的那本是一樣的。
②用于such...as結構中
I don”t like such books as he recommends.我不喜歡他推薦的那些書。
③用于"so +adj. + a/an + n. (單數) + as "結構中
I am not so strong a man as I was.我已經沒有從前那么強壯了。
2. as單獨引導定語從句
as單獨引導定語從句時，先行詞可以是一個詞，也可以是一個句子或短語。例如：
(1) She is late, as is often the case.她遲到了，這是經常的事。(先行詞是整個主句)
(2) To shut your eyes to facts, as many of you do, is foolish.對事實視而不見--你們好多人都是如此的愚蠢。(先行詞是不定式短語)
三、as作介詞的用法
as作介詞，意思是"作為"，"以……身份"。例如：
He came to China as a tourist five years ago.他五年前以游客的身份來過中國。
四、as作副詞的用法
to the same degree or amount; equally "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。
【as的用法】相關文章：
with的用法01-15
as as的用法09-01
the的用法09-01
逗號的用法03-30
before的用法03-24
enjoy的用法09-06
which的用法09-07
allow的用法09-07
be動詞的用法09-04