He claims to be a warrior for freedom of expression, but in reality, he's just someone who uses derogatory words.

He is writing a thesis on paleogeography.

He is working as an agent for the Central Intelligence Agency.

By regularly checking the key performance indicators, you can understand the performance of the company and devise improvement measures.

He is interested in phrenology.

He is interested in ancient mathematics.

I am majoring in parasitology at university.

He is majoring in metallurgy at university.

He is an expert in oceanography.

He learned about the structure of society in his civics class.