Firms produce and sell goods and services. They also hire and use factors of production. Households buy and consume goods and services. They also own and sell factors of production.

• 企业生产并出售物品与劳务。它们也雇佣并使用生产要素。家庭购买并消费物品与劳务，他们也拥有并出售所有生产要素。