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(jié)構(gòu)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(guān)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(dǎo)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(jié)構(gòu)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(dǎo)時間狀語從句

as與when，while都是引導(dǎo)時間狀語從句的從屬連詞，含義都是"當(dāng)……的時候"。但它們有區(qū)別：用when時，從句的動作可以與主句的動作同時發(fā)生，也可以先于主句的動作發(fā)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(fā)生;用as時，主句和從句的動作同時發(fā)生，具有延續(xù)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(dǎo)原因狀語從句

as，because，since都可以表示因果關(guān)系，連接原因狀語從句，含義是"因為，由于"，但它們有區(qū)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(rèn)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(dǎo)讓步狀語從句

as與although (或though)，however (或no matter how)等都可以引導(dǎo)讓步狀語從句，含義是"雖然，盡管"，但它們有區(qū)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(dǎo)的讓步狀語從句用倒裝語序;however引導(dǎo)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(jì)相當(dāng)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(biāo)。