If his father had known, he kept the knowledge to himself.

He was willing to do anything to keep the knowledge away from her!

What was the point in keeping the knowledge to himself?

But, for the moment, I think we must keep the knowledge to ourselves.

Well, I kept my knowledge to myself, and waited to see what would come of it.

If the horse did understand, it kept its knowledge to itself.

He figured the only way to keep the knowledge from being lost was by using it.

She had agreed to keep her knowledge of this a secret.

That, too, he recognized, but kept the knowledge to himself.

There are always a few among my people who keep the knowledge of your people's language.