Questions 22 to 25 are based on the conversation you have just heard.

A．They lived a simpler life than villagers today.
B．They knew fewer people than villagers today.
C．They found it difficult to enjoy themselves.
D．They had nothing to do in the evenings.

A．Because it gives people a sense of achievement.
B．Because most people like doing it every day.
C．Because it is neither biochemical nor poisonous.
D．Because it increases the heart rate and circulation.