He is majoring in moral philosophy at university.

He is a world-renowned zoologist.

He is an expert in paleozoology and has a deep knowledge about the ecology of dinosaurs.

He has a deep interest in paleozoology.

This castle has existed since the medieval times.

'儿' is a Kangxi radical that represents a leg.

The cube of 5 is 125.

He is weak and prone to illness.

He is a handsome guy named Shou.

The military officer plays an important role as a leader in the army.