1.作状语:
You should always review your lessons.
He works hard. 他工作努力。
2.作表语: The class is over.
3.作定语: 副词作定语时置于被修饰词之后
The comrades here give us a lot of help.
4.作补语(包括宾语补足语和主语补足语):
I found all the lights on when I got home last night.