The United Kingdom is a constitutional monarchy.

Her family adopts a matriarchy.

Oligarchy is a political system where a few powerful people rule the country.

Proportional representation is an important system to ensure the fairness of elections.

My company has introduced a layoff system.

He is doing special exercises to strengthen his depressor muscle.

Primitive communism is one of the initial forms of human social organization.

The system of provinces was a part of the ancient political system in Japan.

My class starts at eleven o'clock.

I eat lunch at twelve o'clock.