One part is important.

It is reported that North Korea has conducted another underground nuclear test.

He is spending a lot of time on experimental research.

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.

Cartography is an important field of study for visually representing geographic information.

He is majoring in metallurgy at university.

He is an expert in oceanography.