He is an expert in medicine.

He is learning the basics of elementary learning.

He clenched his lower jaw tightly to endure the pain.

Gagaku is the ancient court ritual music of Japan.

Ecology is a field of study that investigates the interrelationships of organisms in the natural world.

In this experiment, the substance will undergo a chemical change.

This substance undergoes a chemical change when heat is applied.

He is majoring in agronomy at university.

Epidemiology is the science that studies the occurrence and spread of diseases.

I am majoring in political science at university.