USITC贸易数据库中的first unit of quantity是什么意思 2 个回复 - 4671 次查看
还有the second unit of quantity,貌似解释中是说the first is used for tariff purposes and the second unit of quantity might be used for quota or other purposes. 实在不明白其中的意思,跪请高人解答~2013-4-29 19:32 - luxun1712 - 世界经济与国际贸易