“As” 一词拼写简单，用法可不少！“Work as a waitress” 是什么意思？“As…as” 的句式用来做什么？如何用 “as” 表示两件事情同时发生？ 
 
'As' is tiny, but mighty. You can use it in lots of different ways. So, let's have a look at four of them together.
You can use 'as' – number 1 – to compare two people or things.
Tokyo is as big as Los Angeles (more or less)
Number 2 – to describe somebody's job:
I used to work as a waitress. (And no, I wasn't very good)
Or to describe something's function:
Did you know that you can use olive oil as shampoo? Me neither!
Number 3 – to say that something happened at the same time as something else.
You rang me just as I was texting you.
Number 4 – to give a reason like 'because'.
As the sun is shining today, I think I might go for some fresh air after this.
And as you have hopefully been learning something new, why don't you practice one of these in the comments now?
 
用法总结
 
1.  用 “as” 来比较两个人或事物。搭配 “as…as” 可以表示 “一样，不分伯仲”
My house is very small – hers is twice as big.
He is as tall as his brother.
 
2. 用 “as” 来描述人的职业或事物的功能。
He works as a nurse.
You can use coconut oil as cooking oil.
 
3. 用 “as” 描述两件事同时发生。
I was just thinking about you as you rang.
The doorbell rang as I was cooking.
 
4. 用 “as” 引出原因，类似于 “because”。
I didn't go to the party as I was tired.
I forgot to send the email as I was stressed.