Preposition 介词
like:
They are dressed as clowns.
As:
I work as a tour guide.
Adv 副词
as ... as
You are as tall as your father
as ... , 和.. 一样
As always, he said little.
连词 conj
随着
As she grew up, she gain in confidence.
按着什么方式
They did as he said.
Reason
As you were out, I left a message for you.
正如
As you kown, july is leaving for washington.
即使
Happy as they were, there was something missing.
形容词 adj
She is not as pretty.