Fiscal Policy

需求是指在一定时期内，消费者在各种可能的价格水平上愿意并且能够购买的商品或服务的数量。需求受到价格、收入、替代品价格、互补品价格、消费者偏好等因素的影响。

Demand refers to the quantity of a good or service that consumers are willing and able to purchase at various price levels during a given time period. Demand is influenced by price, income, prices of substitutes, prices of complements, and consumer preferences.

供给是指在一定时期内，生产者在各种可能的价格水平上愿意并且能够提供的商品或服务的数量。供给曲线通常向右上方倾斜，表示价格越高，供给量越大。

Supply refers to the quantity of a good or service that producers are willing and able to offer at various price levels during a given time period. The supply curve typically slopes upward, indicating that higher prices lead to greater quantities supplied.

供需图表是经济学中最基本的分析工具。通过分析均衡点的移动，我们可以预测价格和数量的变化方向。

Supply and demand diagrams are the most fundamental analytical tool in economics. By analysing shifts in the equilibrium point, we can predict the direction of changes in price and quantity.