一、as作连词的用法
1.as...as的用法
as...as意为"和……一样",表示同级的比较。使用时要注意第一个as为副词,第二个as为连词。其基本结构为:as+adj./adv.+as。例如:
(1)Your pen writes as smoothly as mine.你的钢笔书写起来和我的一样流畅。
(2)This film is as interesting as that one.这部电影和那部电影一样有趣。
其否定式为not as/so+adj./adv.+as。例如:
This dictionary is not as/so useful as you think.这本字典不如你想象的那样有用。
若有修饰成分,如twice,three times,half,a quarter等,则须置于第一个as之前。例如:
Your bag is twice as expensive as mine.你的袋子比我的贵一倍。
2、as引导时间状语从句
此时,as译作“当……时候”,可以放在主句之前,也可以放在主句之后。例如:
He smiled as he said goodbye to me.
他向我道别时微笑了一下。
As she was walking in the park,she heard a girl singing.
她在公园里散步时,听到一位女孩在唱歌。
I sang an English song as I went along the river.
我边沿河边走边唱英文歌。
3.as用作连词引导原因状语从句
as,because,since都可以表示因果关系,连接原因状语从句,含义是"因为,由于",但它们有区别:because表示的语气最强;as一般放在句首,语气较弱,较口语化;since常常用在书面语中,表示多为对方已知的、或稍加分析便可得知的原因,有时可译作"既然"。例如:
(1)He will succeed because he is in earnest.他一定会成功,因为他很认真。
(2)Since you are so sure of it he”ll believe you.既然你对此如此有把握,他会相信你的。
(3)As rain has fallen,the air is cooler.因为下过雨,空气比较清爽。
4、as引导让步状语从句
此时,as译作“尽管”。当as引导让步状语从句时,不把as放在从句的开头,而是将充当从句主要成分的形容词、副词、分词、动词原形或不加冠词的单数可数名词置于前面。
(1)将表语放在句首,再将as放在表语和主语之间。例如:
Child as he is,he knows quite a lot of things.
虽然他还是个孩子,但他懂得很多事情。
(2)将状语放在句首,再将as放在状语(副词)和主语之间。例如:
Much as she likes,she will not take it.
尽管非常喜欢它,但她也不会拿走的。
(3)将主动词放在句首,再将as放在主动词和主语之间。例如:
Try as he did,he didn’t succeed.
尽管他努力了,但还是没有成功。
二、as作介词的用法
as作介词,意思是"作为","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来过中国。
三、as作副词的用法
to the same degree or amount;equally"相同地","同样地"。例如:
They don”t have as many airplanes.他们没有同样多的飞机。
四、as作关系代词的用法
as引导英语从句时,在从句中充当主语、宾语、介词宾语或表语,既可以指人,也可以指物。
1.as单独引导定语从句
as单独引导定语从句时,先行词可以是一个词,也可以是一个句子或短语。例如:
(1)She is late,as is often the case.她迟到了,这是经常的事。(先行词是整个主句)
(2)To shut your eyes to facts,as many of you do,is foolish.对事实视而不见--你们好多人都是如此的愚蠢。(先行词是不定式短语)
2.as引导定语从句与其他词连用
①用于the same...as结构中
This is the same book as I read last week.这本书和我上周读的那本是一样的。
②用于such...as结构中
I don”t like such books as he recommends.我不喜欢他推荐的那些书。
③用于"so+adj.+a/an+n.(单数)+as"结构中
I am not so strong a man as I was.我已经没有从前那么强壮了。
You need to be able to work as part of a team.
你必须能作为团队的一员去工作。
She used her family's history as a base for her novel.
她以她的家族史作为小说的素材。
My new job is much the same as the old one.
我的新工作和旧工作差不多。
Take as much time as you like.
你想花多少时间就花多少时间。
As often as not, he's late for work.
他上班往往迟到。