My major is mechanical engineering.

He is an expert in systems engineering.

He is majoring in astronautics.

He learned about the structure of society in his civics class.

He is an expert in enzymology and has conducted many studies in that field.

He is an expert in enzymology and conducts many researches.

Software engineering is a field of study related to the design and development of computer programs.

Palaeoclimatology is the science that studies the past climate of the Earth.

He is immersed in the study of geometrical optics.

He is attending a college preparatory school.