In the past, I had learned to keep my thoughts to myself.

She had learned early to keep her thoughts to herself.

George decided to keep his thoughts to himself for the time being.

"Those who think so should keep their thoughts to themselves."

Better to keep his thoughts on the here and now.

Perhaps he could keep his thoughts to himself until she was free of him.

She had never been able to keep her thoughts from going back.

And yet, she knew him well enough by now to keep her thoughts on the subject to herself.

She had done everything these last days to keep her thoughts to herself.

It would be better to keep his thoughts from her as best he could.