被动语态和系表结构的区别?用自己的话告诉我,列举一些经典的例子!

被动语态有被动的意义,如:This project was finished last year.
系表结构无被动意义.如:I'm a student.

he is a boy .
系表结构是说明主语的状态,职位等.
系动词后是形容词,名词等
被动是动词的被动式!
the work is being done .