Abstract algebra is a branch of mathematics that studies algebraic structures.

The Paleolithic is the first era of human history.

My grandfather was born in the 1900's.

Abstract algebra is a field of mathematics that studies algebraic structures in an abstract way.

I am studying Modern English.

The Cultural Revolution is a part of China's history.

The Third International was a historically important organization.

The Mesolithic is the era between the Paleolithic and the Neolithic.

I studied linear algebra at university.

He continues to practice in search of complete enlightenment.