He was running while holding a bag.

He always carries an umbrella around.

He is majoring in chemistry at university.

Understanding the structure of atoms is a fundamental part of physics.

He is an expert in chemistry.

I commute to work every day on the circle route.

Understanding data structures is important for improving programming skills.

Organic solvents play an important role in chemical reactions.

The four kana refers to the four kana pairs of じ, ぢ, ず, づ.

Please cut this apple into four pieces.