四、作介词，

1. 表示 “好像(某人)”，例如:

They entered the building disguised as cleaners. 他们化装成清洁工人的模样进入大楼。

2. 表示“作为，当作”，例如：

I found a job as a teacher. 我找了一份教师的工作。

3. 表示“当某人是(某身份)时。例如：

As a child, she was sent to three different countries. 她儿时去过三个不同的国家。

4. 表示“因某人是(某身份)”，例如：

As her private secretary he has access to all her correspondence. 他是她的私人秘书，能接触到她所有的信件。

注意1：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。例如:

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

She works as a nurse. (状语)

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

注意2：as和like都可以作介词，但意义不同。as表示“以实际的身份或地位”。 like则表示“与…相似，以与…相类似的方式”。例如：

(1). He spoke as a teacher.

(2). He spoke like a teacher.

句(1)的意思是：“他作为老师发言”或“他以老师的身份发言”。句(2)的意思是：“他讲话很像是老师”。

五、用于一些固定搭配

1. as good as差不多，几乎

Don’t worry, the matter’s as good as settled. 别担心，问题差不多已经解决了。

When the car was repaired, it looked as good as new. 这辆汽车修理好的时候，看起来差不多就像新的一样。

2. as if /as though 似乎;好像

He behaved as if nothing had happened. 他装着若无其事的样子。

She treats him as though he was her own son. 她待他好像待自己的儿子一样。

另外，as if可以接一个动词不定式短语。例如：

He waved his hand to me as if to have something to tell me. 他向我挥手好像有什么要告诉我。

3. as well as 同(一样也);和;还

Joan can speak Chinese as well as English. 琼能讲英语还能讲汉语。

He spent all his money, as well as wasting his time. 他不仅浪费了时间，还花光了他所有的钱。

4. such...as, such as 像……这样的

I bought a lot of fruits, such as apples, oranges, bananas and so on. 我买了许多种水果，像苹果，桔子，香蕉等。

We had such books as you never saw. 我们有一些你从未看过的书。

5. as for 至于某人(某事物)

We had a delightful weekend in the country. As for the traffic, we had no difficulty. 在乡下我们度过了一个愉快的周末。至于交通，我们没遇到任何困难。

6. as to 关于某事物;提到某事物

I don't know anything as to the others. 至于其他，我一无所知。

7. so as to ... 以便, 为了

Students should take notes so as to make revision easier. 学生应当记笔记，以便容易复习。

8. as a matter of fact 其实;实际上

As a matter of fact, I’m very fond of housework. 其实，我很喜欢做家务。

9. as a result 结果 (发生某种情况)

As a result， he had been given an excellent job. 结果，他得到了一份极好的工作。

10. as long as 只要

You may borrow this book as long as you promise to give it back. 只要你答应归还，你就可以把这书借走。

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，应付自如。