1-市场参与者(消费者)的数量增加,因为买方的人数增加,所以需求曲线右移
Mankiw Ch.4 "[Number of buyers increase,] quantity demanded in the market would be higher at every price, and the demand curve shift to the right."
2-生产者对未来的预期使得起供给曲线移动
Mankiw "The [quantity of products] a firm supplies today may depend on its expectations of the future."