Homo erectus is considered one of the ancestors of mankind.

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

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.

The tree is the biggest tree in the park.

Please attach this file to the email.

He said that his blood type is A.