He is an expert in probability theory.

Einstein's theory of relativity is one of the important theories in physics.

A DD debate is unfolding between him and her.

He is writing a thesis on the yellow peril.

His idea is pure armchair theory and cannot be applied to real-world problems.

Christology is a part of Christian theology that studies the nature and role of Jesus Christ.

He is playing a foolish character named Rho.

He likes to take a walk in the park at dusk.

He is spending a lot of time on experimental research.

The Calopteryx cornelia is a species endemic to Japan, and it has beautiful wings.