He was forced to drop out of school due to poor grades.

He had to drop out of school because he broke the school rules.

He has a deep interest in literature.

I studied in the library with my schoolmate.

He is majoring in veterinary medicine.

He is studying mechanics in depth.

He is majoring in geography at university.

He is an expert in pharmacology.

He is majoring in pharmacy.

He is known as an expert in gerontology.