回答：as意为“作为”时,一般是介词,如,
He wanted me to go with him as his interpreter.
His father has been working as a teacher.
as作为连词,一般引导原因,时间状语从句,方式状语从句,比较状语从句和让步状语从句,如：
As I was watching TV,I heard a terrible noise.
I can't go with you as I have too much to do today.
I can’t speak English as well as she does.
We must do as he said.
Tired as he was,he kept working until very late at night.
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