It is known that passive smoking has a negative impact on health.

He is dedicated to the study of immunochemistry.

Homo erectus is considered one of the ancestors of mankind.

He swore to protect that secret even at the cost of his life.

He decided to change his character.

If you rephrase that complex theory in simpler terms, it's just common sense.

He daringly accepted the challenge.

His existence is important to me.

He was abusing his power.

I went to the market accompanied by my mother.