农业生产和手工业生产的分工,私有制的产生,城乡的分化,商品生产的出现,使原始公社公有制下的产品交换,发展到私有制下的商品生产和商品交换。在公社公有制下的产品交换,生产者不是以交换为目的而生产商品,而是将自身消费后剩余的产品去换回需要的产品;在私有制下,则是以交换为目的而生产商品。剩余产品交换和商品交换,虽同是物物交换,但这两者是有区别的:前者,是简单的偶然的价值形态下的物物交换,要在交换发生时才成为商品;而后者才是扩大的价值形态下的商品生产和商品 The division of labor between agricultural production and handicraft production, the emergence of private ownership, the differentiation of urban and rural areas and the emergence of commodity production have enabled the exchange of products under the public ownership of primitive communes to commodity production and exchange of commodities under private ownership. In the communal public exchange of products, instead of producing goods for the purpose of exchange, the producers exchange the remaining products after they have consumed them for the products they need, while in the case of private ownership they produce goods for the purpose of exchange. The exchange of surplus products and the exchange of goods, though in the same way as the exchange of things, are distinguished from each other: the former is the exchange of things under a simple contingent value form, and becomes the commodity only when the exchange occurs It is an expanded form of commodity production and commodities