英语 同位语 到底怎么用

语法里讲同位语紧跟名词或代词之后，但 we are all 。。。 这句 为什么在be之后？
we are all we all are 到底那个对？
另外，we student shall be on time to go to school. 为什么就紧跟名词之后？
同位语到底该怎么用？
谢谢。

I'm wangNan,a student of No.1 Middle School. I have a gooa friend,Jim.He' an USA girl.We are both in Class Two,Grade Eight.She is 15 years old,one year older than me. We both study hard.I'm good at physices,but she's good at math.We often help each other with lessons.Both of us like helping others. We both like sports very much.Jim enjoy playing basketball.but Ilike palying soccer. She likes green but Ilike red. Tough we are different in my ways,we are good friends