His explanation was impossible to understand.

It is important to understand the importance of health.

The greater part of the time is spent on work.

This project was partially successful.

In French, the partitive article plays a very important role.

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

I am majoring in physical chemistry at university.

He is a world-famous physicist.

He is an expert in aerodynamics.

He is an expert in fluid mechanics.