一、关税与贸易总协定自生效以来,每一轮的多边贸易谈判为什么均把关税谈判作为最重要的议题之一?二、什么是关税的“重新谈判”,它与每一轮的多边关税谈判有何不同?三、传统的关税减让谈判方式是以什么为基础的?四、为什么说“主要供应国原则”是传统的关税谈判方式中的一项主要原则? I. Since the entry into force of the General Agreement on Tariffs and Trade, why did each round of multilateral trade negotiations consider tariff negotiations as one of the most important topics? Second, what is the “re-negotiation” of tariffs and the multilateral tariffs of each round? What are the differences in negotiation? Third, what is the basis of the traditional tariff reduction negotiation? Fourth, why is it that the principle of “main supplier country” is a major principle in the traditional tariff negotiation?