This ancient proverb, 'know the other side and yourself, and you will not be in danger in a hundred battles', teaches us the importance of understanding ourselves and others.

He didn't know that fact.

He is really knowledgeable and always teaches us new information.

He found out the truth and was surprised.

It's important to believe in yourself.

He is feigning ignorance about that problem.

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

He knows that pain through his own experience.

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

God only knows what he is thinking.