He is an expert in biophysics.

He is an expert in nuclear physics.

He is an expert in nuclear physics and has won many awards in the field.

He is an expert in astrophysics, and his research is highly valued around the world.

He is an expert in applied physics.

He is known as a person with learning.

He solved a large number of problems.

Understanding numbers is important for solving math problems.

He was bedridden with illness for several days.

I can't solve this problem because there are too many numbers.