Again using an example from agriculture, farmers periodically plant less wheat or raise fewer cattle if the prices for those commodities give too little return for the costs involved.

• 再举一个农业方面的例子。如果农民们种的麦子或养的牛就成本而言得到的价格回报太少,他们就不时地进行调整,少种麦子或少养牛。