We visited the ancient dolmen.

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

By regularly checking the key performance indicators, you can understand the performance of the company and devise improvement measures.

Her family adopts a matriarchy.

The United Kingdom is a constitutional monarchy.

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.