A-level经济学的知识点众多，且内容较难。日常的知识积累非常重要，下面就来看一下经济学中关于Price system的详细解析。
In the free market, the price acts as a rationing device, a signal, and an incentive.
Rationing:The low price ensures that high amounts of the product will be bought, and reflects the fact that the product is not relatively scarce.
Signaling:Price is a key piece of information for both buyers and sellers, and is a result of the transactions of the buyers and suppliers.
Incentive:Changes in prices act as an incentive for buyers and sellers to change their behaviour.
Resource allocation:The functions of price as rationing, signal and incentive works together and rescources are allocated to different uses.
价格作为配给、信号、诱因以及配置机制。
配给：在市场经济中，由谁获得什么商品和多少商品，都是通过价格来进行的——价格的高低决定了某个消费者是否购买或者购买多少。
信号：价格的变化给消费者和生产者信号来决定他们的行为。
诱因：如果是需求上升导致的高价格会使生产者有更高的利润，从而诱使生产者扩大生产；同时高价格也会诱使消费者减少这个商品的购买，或者还会寻找这个商品的替代品。
资源配置： 价格在市场中的以上三种功能共同作用，就完成了资源在市场经济中的配置。
