He is our class representative.

The steepest descent method is one way to solve optimization problems.

He is an expert in geophysics.

It took several hours to restore power after the blackout.

My grandfather was born in the 1900's.

My laboratory is on the third floor of the university.

There is a proverb, 'a cornered rat will bite a cat,' which means that a person driven into a desperate situation will fight back even against an opponent they would normally fear.

There is an old incandescent light bulb in my room.

It is generally believed that the life of the middle class is stable.

He emphasized the importance of class struggle.