Grammar：useofas.doc

Grammar:use of “as”

as [D.J.:æz, əz][K.K.:æz,əz]adv.同样地, 一样地
She is as tall as her mother.她和她母亲一样高。
The dining room was twice as big as the Tom's.这个餐厅比汤姆的餐厅大一倍。
This is as difficult a problem as you are likely to meet.像这样的难题, 你可能会碰到。
prep.(表示时间)当还是…的时候
As a schoolboy, he showed every sign of genius.当他还是个小学生的时候, 就显示出了天资聪慧。
(表示方式)以…的身份, 以…资格, 作为; 以…形式, 以作为; 以…角色, 扮演…角色; 如同, 像；(表示结果)成为, 看作, 看成
We had better treat it as a joke.我们最好把它当作玩笑。
(表示目的)为了, 以…为目的
The dykes were built as a protection against the sea.建筑堤坝是为了防止海水泛滥。
(表示举例)例如, 诸如…之类的
We talked about such subjects as the weather我们谈论了诸如天气之类的话题。
conj.在…期间, 当…时候
I was coming in as he was going out.我进来的时候, 他正出去。
尽管, 即使, 虽然
Intelligent as you are, I suspect you will fail.尽管你聪明, 我猜想你会失败。
像…一样；由于, 因为
As you weren't there I left a message.因为你不在那里, 我留了个信儿。

1、 用作从属连接词，引出时间、原因、方式、比较、让步状语从句
时间Light waves weaken as they spread out from a source.光波从光源扩散后，强度减弱。
原因As liquids and gases flow, they are called fluids.因液体和气体能流动，称为流体。
方式As sound waves are, light waves are different in frequency.光波和声波一样，有不同的频率。
方式 A digital compute employs numbers, as we frequently do in paper and pencil calculations.电脑使用数字，正如人常常用纸和铅笔计算时使用数字一样。
比较 It is well known that wood is not as strong as steel.
让步The various losses in a machine , great as they are , do not in any way contradict the Law of Conservation of Energy.机器中各种损失很大，但与能量守恒并不冲突。
让步Complicated as the problem is , the electronic brain can solve it in a short period of time.尽管那个问题复杂，电脑在很短的时间把它解出。

有时AS所引出的是状语从句，但在翻译时要译成定语从句。
Lights as it comes from the Sun is a mixture of light of many different frequencys and of many different colours.来自太阳光是混合频率和混合颜色。
The metals as (they are) discussed in Lesson Two， are not pure metals but alloys.第二课中讨论的金属不是纯金属，是合金。

2、 用作介词
⑴与一些动词如consider,use,describe,difine等搭配，引出主语补足语或宾语补足语。
Engineering is considered as an applied science.
One kind of heat engine uses atomic energy as a source of heat.有一种热机使用原子能作为热源。
The atom of any element is pictured as resembling the solar system.任何元素的原子，可以描述成太阳系一样。My brother resembles me in looks我弟弟和我长得很像。

⑵表示“作为”的意思，引出的短语一般说明主语
Electricity is especially convient as a source of mechanical power.电作为机械的动力源，用起来特别方便。
As a “machine tool”, the laser beam has been found useful in cutting,drilling,and welding metals.激光束作为一种工作母机，在切割钻孔和焊接金属方面是非常有用的。

3、 用作关系代词，引出定语从句
⑴代表主句中的某个名词，与主句中such,the same或as(副词)连用，在从句中as做主语、宾语或表语
This is the same materical as is used in building the bridge.
A proton and neutron has about the same mass(质量) as a hydrogen atom.
Such a complex machine as the diesel engine is simply a combination of simple machine.象柴油机这样复杂的机器只量简单机械的组合。
In processing petroleum ,as many fractions as are contained in it are to be separated from each other.炼油过程中，油中的不同的馏分要分馏出来。
⑵代表整个从句
As was discussed before, copper seldom is used in its pure form except in the electrical industry.
As has been pointed out ,transistors are devices that can be used instead of vacuum tubes.正如指出的那样，晶体管可以代替电子管。
The material is elastic ,as is shown in the figure.如图所示，这种材料具有弹性。

4、 用作关系副词，引出定语从句
Electromagnetic waves travel at the same speed as light.电磁波与光速相同。
Sound is conducted through steel in the same manner as thought air.声音在钢中的传播方式与空气中相同。

5、 与as及其他词组成词组，如so…as,as…as,so as to,as well as,as a rule,as a result等
As (so) far as…,so (as)long as..;as though (as if)…,as such…,so…as to. Such…as to,as well. As for(at to)…,as it is ..,as it were, as regards, as soon as, as yet.according as.
As far as construction is concerned, the computer is similar to the human brain.从结构上年地，电脑与人脑很相似。
The earth behaves as thought it were a large magnet.地球的行为象一个大磁铁。
The laser is a source of highly directional ,monochromatic ,coherent light ,and as such it has revolutionized some optical problems.激光是一种具有高度同向性的，单色的，相干光的光源，它给一些光学问题带来革命性变化。
Ultrasonic frequencies are so high as to be out of the range of the human ear.超声波的频率高得超出人耳的听觉范围。
The computer is programed in such a way as to gather a wide range of information from outer space.这台计算机的程序设计使得它能多外空间收集广泛的信息。