我们在第二讲中曾经提到 ,当边际收益等于边际成本时 ,总收益与总成本之差最大 ,于是生产资源的配置达到最大效率或最适度 (或称最优 )的经济状态 ,福利经济学家通常称之为“帕累托最优” ,也即社会效率水平。但是 ,并非所有的商品或服务都能达到社会效率水平 ,对于某些商品或 As we mentioned in the second lecture, when the marginal revenue is equal to the marginal cost, the difference between the total revenue and the total cost is the largest. Therefore, the allocation of production resources reaches the maximum efficiency or the optimal (or optimal) economic status. The welfare economy Scholars often call it “Pareto Optimal,” which is the level of social efficiency. However, not all goods or services can achieve the level of social efficiency, for some commodities or