noun clause

Its having a noun and verb in a sentence.

Example :

I don’t know her ------->not a noun clause

Correct sentence was:

I don’t know who is she .

Example 2 :

They don’t know him.

Correct sentence was:

They don’t know who is he .

Example 3 :

That is very interesting

Correct sentence was:

What he is doing very interesting

Example 4:

It is a  mystery.

Correct sentence was:

Why he did that is a mystery .