being=to be(成为）

一般用于一些目的,方式状语的句中
如:
Being a teacher is rather tired.
To be a teacher is rather tired.

Seeing is believing.
To see is to believe.

being用于介词后和其他短语组成介词宾语。
to be也一样。

Before being a student, I'm very bad.

I want to be a student.

being 和to be都是非谓语.
某些情况可以通用
如眼见为实:Seeing is believing.
=To see is to believe.