存著再看年 06:49 Production Possibilities Curve as a model of a country’s economy | AP Macroeconomics | 可汗学院
会员 Changes in Market Equilibrium How the equilibrium price or quantity might change due to changes in supply or demand More free lessons at: 在家DIY的最佳美甲://www.khanacademy.org/video?v=NgPqyM3I_8o
