He always proactively suggests new ideas.

He is writing a thesis on the theory of general relativity.

He is studying the traditional Baijiaxing (Hundred Family Surnames) of China.

He is interested in ancient divination techniques.

General relativity is a theory of physics proposed by Einstein.

He is good at solving technical problems.

He always has an optimistic attitude.

His music is very avant-garde, and some people might not understand it.

He is facing economic problems.

This word is etymologically derived from Latin.