Sentence examples for really not known from inspiring English sources

Had the C.E.O. of a large corporation really not known about employer taxes?

It's been a puzzle for 75 years, and it's still really not known what causes this.

Had she really not known who Kris Kristofferson was? Knowing Abi, it's very possible.

Had she really not known who Kris Kristofferson was? Knowing Abi it's very possible.

"All of a sudden, this health effort, that was really not known by very many people, became known to millions," she said at a recent TEDMED Talk.

"All of a sudden, this health effort, that was really not known by very many people, became known to millions," she said at a recent TED Talk.

Do they really not know?

Did they really not know what they were getting?

Do millennials really not know how to cook?

Or, could they really not know any better?

Did her support team really not know about it?