He is a famous historian and has written many history books.

He is majoring in history at university.

He is trying to hide his embarrassing past.

He recognizes the importance of oral history.

He claims to be a socialist.

It's better for him not to know the truth. After all, ignorance is bliss.

He is feigning ignorance about that problem.

He knows that pain through his own experience.

I have no way of knowing what he is thinking.

He is working hard to make his abilities known to the world.