As的各种用途在英语里，“as”这个字神通广大，有各种用法，下面便是其中九种：一、用作介词。

用作介词的as1.表示“如，像”。

例如：They got united as one man./She spoke of me as her dearestfriend.2. 表示“作为、当作”。

例如：As a League member, you should think more ofothers.3. 与某些动词搭配，表示“把……当作……”，如：look on…as…, regard…as…,treat…as…, consider…as…, think of…as…, see…as…等。

其中consider…as…中的as可以省略。

as与famous或known搭配，表示“作为……而出名”。

例Linda worked for the Minnesota Manufacturing and Mining Company, ________ as 3M.A. knowingB. knownC. being knownD. to be known解析：如果熟悉be known as这一短语，运用有关非谓语动词的常识，可选出正确答案B。

例如：（1）As the new manager of the company, Wilcox assured the staff that he would work for the benefits of the company.（2）The scenery here is beautiful as a picture.二、用作表示“程度”的副词。

例如：修饰形容词或副词，表示程度，意为“同样地”。

例如：He swims fast, but I swim just as fast. 但它通常构成表示比较的结构“as…as…”，“not as…as…”。

此结构中第一个as是副词，第二个as是连词。

否定结构中的副词as可以由so代替。

as…as possible /one can也属于此用法。

例如：It is generally believed that teaching is as much an art as it is a science.（3）You have performed well. Other students' performance is as good.三、用作连词的as(一) 用作从属连词，引导“比较”副词从句。

例如：（4）The friendship between us is as strong as a rock.（5）Can our runners run as fast as they used to?（二）用作从属连词，引导“时间”副词从句。

例如：1.引导时间状语从句，表示“当……的时候”，其用法与when和while类似。

此用法中as多表示从句与主句动作同时进行，意为“一边……一边……”，一般不与状态动词连用。

例如：She sang songs as she did her homework.as 还可以表示一动作紧接着另一动作发生，说明另一动作的结果，有“随着……”的含义。

例如：As time went by, we found he was an honest man./As he grew older, he lost interest in everything except gardening.例1 It w asn’t until nearly a month later________ I received the manager’s reply.A. sinceB. whenC. asD. that解析：本题的as中与when一起作为干扰项，容易使考生往时间状语从句上思考，事实上本题是强调句，正确选项是D。

（6）As the new teacher entered the classroom, the pupils clapped their hands.（7）Alex caught sight of Nancy as she was getting on the bus.（三）用作从属连词，引导“方式”副词从句。

He looked forward，，to the completion of the building例如：（8）You may act as you think fit.（9）It is safer for you to do as you are told.这些由"as"引导的从句可以节缩，如：（10）It is safer for you to do as told.（11）The meeting will be held as （it has been）scheduled.（12）The weather here is not mild as （it is）in your country.（五）用作从属连词，引导“原因”副词从句。

引导原因状语从句，表示“由于，因为”，相当于because, 但通常置于句首。

例如：1. As he is a qualified doctor, I trust his advice on medical matters.2 _____ modeling business is by no means easy to get into, the goodmodel will always be in demand.A. WhileB. SinceC. AsD. If解析：本题中as干扰性很强，很多考生误以为是原因状语从句，但仔细分析不难发现正确答案应是A（while表示“只要”）。

例如（13）As the weather is fine, let's go fishing.(14）We helped Tony, as he was a good man.（六）用作从属连词，引导“让步”副词从句。

引导让步状语从句，通常可与although或though通用，但语序不同，although 或though用于句首，as用于倒装结构。

例如：Young as I am, I already know what career I want to follow. /Although（或Though）I am young, I already know what career I want to follow. as 表示让步用于倒装结构，通常将从句的表语、状语或动词前置。

如果表语有冠词a/an, 需去掉。

例如：Great scholar as he is, he is lacking in common sense./Much as I like you, I couldn’t live with you.例3 _____ he has limited technical knowledge, the older worker has a lot of experience.A. SinceB. UnlessC. AsD. Although解析：as 虽然有引导让步状语从句用法，但本题不是倒装结构，故正确答案应是D。

（15）Improbable as it seems, he is now Managing Director.（16）Young as Sam is, he has performed his task creditably.（七）用作关系代词，引导形容词从句。

1. 引导限制性定语从句，先行词前通常有as, so, such, same等修饰语。

例如：He smokes as expensive a cigarette as he can afford.He will marry as pretty a girl as he can find./My hometown is no longer the same as it used to be./As many people as are present will be given a present.在此种用法中，同学们要注意与结果状语从句的区别。

比如：A: The teacher asked us such a difficult question that none of us could answer it. B: The teacher asked us such a difficult question as none of us could answer. A句为结果状语从句，而B句则是定语从句。

2. 引导非限制性定语从句，用来指代整个主句（即先行句），表示“这一事实，那一情况”。

从句可以位于句首、句中或句末。

例如：As is reported in the newspapers, talks between the two countries are making progress.Grammar is not a set of dead rules, as has been said above.We stand when the national anthem is played, as is the custom.例6 ______ I explained on the telephone, your request will be considered at the next meeting. A. When B. After C. As D. Since解析：根据句意，选项C是正确答案。

as表现的正是本点所讲用法。

例如：（17）Is this the same thing as you showed me before?（18）You can visit such places as you want to.（四）协助组成短语与句型。

例如：（19）So as to: They departed early so as to reach the airport early.（20）We have touched on the basic issues. As for thorny problems, let's look into them later.（21）As long as you work hard, you will make it.（22）I'll help you as best I can.（23）Maria's idea is not so much a solution as a proposal to sound out our views on the project.来So （As）far as I know,源: as if / as though。