He was calculating in his head.

It is important to understand the importance of health.

He is an expert in computational linguistics and is involved in the development of artificial intelligence.

He should stop his selfish behavior.

There are many historical buildings in the central part of this city.

We went to see a movie in the town center.

We chose Kyoto as the center of our trip.

He plays a central role in this project.

He loves physics and studies it in the library almost every day.

I am majoring in physical chemistry at university.