He saw them often enough to come to know their nature.

For now, only he and I can know its nature.

Any one who knows him well enough to know his real nature will tell you so.

They do not know the true nature of these young men and women.

If I know human nature, that man is different from any other you have had to do with.

But they do not know its nature, that is clear.

We were the only ones who knew their true nature.

Race officials said he was taken to a local hospital, but they did not know the nature of his problem.

"I should like to know the nature of your relationship."

On the other hand, everyone knew his nature at home, they might as well start finding out here.