下面是小编整理的一些关于as 用法总结， 希望让大家更好地认识as这个单词，提高英语水平。

(一)、As =Since 作"既然"、"由于"解,引导原因状语从句,常用来表示已为人们所知或显而易见的原因或理由。

如: As he’s been ill for ages, I will help him.

As / Since you're not feeling well, you may stay at home.

As he wasn't ready , we went without him

2. .as作连词的用法:

1.作“在-------期间，当----的时候”引导时间状语从句.注意与when、 while的用法区别。

①下列情形时,只用as, 而不用when或while。

1)用于表示同一个人的两种动作交替进行,指一边----一边. 如:

The girl sings as she goes to school.

He looked behind occasionally as he went forward in theforest.

2)表示两个同步发生的动作或行?意思是随着-----的发展.如:

As time went on / by, she became more and more beautiful.

As children get older, they become more and moreinterested in everything.

3)表示两个短暂行为或事情几乎同时发生.如:I watched her as she read the book.

I thought of it just as you opened your mouth.

Just as the flying worm hit her face, she gave a loudcry.

4)接在名词后面表示某一个年龄段时.如:

As a young man, he was active in sports.

②when作"当……的时候"解,可以指较短的(一点)时间,也可指一段时间。如:When I was at college, I could speak several foreignlanguages. When the clock struck twelve, I had slept for 2hours.

③ while常表示一段较长的时间或一个过程,强调主句谓语动词与从句谓语动词同时发生。如:Work while you work. Play while you play.

3. As =in the way that作"像"、"按照……的方式"解,引导方式状语从句。如:

Do as I told you.

Remember, you must do everything as I do.

4. 用于as--- as或not / so/ as ----as中,前一个as是副词,后一个as是连词,引导比较状语从句。

如:They helped the old as much as possible.

I don't speak English so/ as well as she does.

5. 表示虽然,尽管等,引导让步状语从句,常用倒装语序,模式为:

adj. /adv. / n.+as +主语+谓语+主句。如: Young as he is, he knows much.

Tired as they were, they walked on.

(二)、 as作关系代词,引导定语从句,表示正如,这一点.如:

He is very careful, as we all know.

As is well-known,Taiwanbelongs toChina.

另外,当先行词被the same, such等词修饰时,常用as来引导定语从句。如:

Such a clever girl as she can learn anything quickly.

I was reading the same book as he bought yesterday.

(三)、as作介词的用法.

1.表示好像。如:He dressed as a policeman.

2. 表示作为当作。如：I found a job as a guide.

3. 当某人是某身份时。如：As a child , she was sent to abroad.

4. as引导的介词短语大多用作状语,as译为"作为";少数情况可引起宾语补足语。如:

As a Party member, I'll take the lead in everything. (状语)

She works as a model. (状语)

She has me as one of her best friends.(引起宾语补足语)

(四)、as作副词的用法

1 表示与------等同。如：This dress istwice as expensive as that one. 2 像，如等。如：As before, he remained unmoved.

总之，通过以上的分析，我们对as的词性和用法有了比较全面的理解和把握，才能在实际的运用中做到心中有数，应付裕如。

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)This film is as interesting as that one.这部电影和那部电影一样有趣。

(2)Your pen writes as smoothly as mine.你的钢笔书写起来和我的一样流畅。

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。

总结

1.as…as结构中，要使用形容词或副词的原形。

2.as…as结构用于肯定句或否定句，so…as只用于否定句，用来表示“不如……那样……”。值得注意的是：它表示的内容总是前者不如后者。使用副词表示“不相等”的句型中，“not as/so…as…”中的not要和助动词do,does,did等一起放在行为动词前，来构成否定句

3.as…as结构中，若出现名词，一般将名词放在as…as中间。若有形容词作定语修饰单数可数名词，其前的不定冠词a/an，须放在形容词之后。

4.as…as结构中如出现表示倍数的词，应放在as…as结构之前。如：

Our school is four times as large as yours.我们的学校比你们的学校要大四倍。

5.as…as结构后接具体数字时，是表示长、短、高、矮、重、轻等的程度，而不是表示两者的比较。如：

Some stones weighas much as fifteen tons.有些石头重达十五吨。