Still, he knew when to keep his comments to himself.

She never seemed to know when to keep quiet and let him work.

He never seems to know when to keep his mouth shut.

The best people in the field were doing everything they knew to keep him alive.

Yet it was the only way he knew to keep her safe.

And must have the good sense to know when to keep it private.

He should know enough to keep in touch with me.

I left it to him to make the decision, but he knew to keep watch.

By now he knew to keep his comments to himself.

The best way I knew to keep those two from doing their job was to find them first.