principle of effective demand

例句：

1. 1. The policy of increasing government spending has been a cornerstone of the economic recovery.
   增加政府支出的政策一直是经济复苏的基石。
2. 2. The demand for oil is expected to increase as global warming affects more countries.
   随着全球变暖影响到更多国家，对石油的需求预计将会增加。
3. 3.The principle of effective demand suggests that when prices are high, consumers will buy less and businesses will produce less.
   有效需求原理表明，当价格高时，消费者会购买较少，企业将生产较少。