Can I use these interchangeably?

I can't comment on something I don't know about.
I cannot comment on something I have no knowledge about.
I cannot comment on a subject I know nothing about.

Question

Can I use these interchangeably?

I can't comment on something I don't know about.
I cannot comment on something I have no knowledge about.
I cannot comment on a subject I know nothing about.

Answer

Yep, all three sentences are natural and can be used interchangeably. The first one is the most common, while the last two sound a bit more formal and precise.

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