whether or no，是合起来用的吗，中间不能加东西吗

可以加，不加实际上是“提前”
I don't know whether he will come or not.
I don't know whether or not he will come.

不是。可以只用whether, 也可以加or not. or not的位置可以挨着whether, 也可以在最后。
I don't know whether I should laugh.
I don't know whether to laugh or cry.
I don't know whether I should laugh or not.
I don't know whether or not I should laugh.

能加