He didn't know that fact.

He found out the truth and was surprised.

He is really knowledgeable and always teaches us new information.

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.

His painting is very realistic, it's just like a photograph.

He is a perfectionist, so he is very strict about his work.

He always looks at things like a pessimist.

He is always an optimist, believing in a bright future even in difficult situations.

He is a true humanitarian, always striving to alleviate the suffering of others.

He is a positivist who thinks based on scientific evidence.