易货贸易合同项下出口货物时，经营单位或其代理人应填写出口报关单向出境地海关申报，并提供( )。

多项选择题进口以下药品和药材，经营单位向海关交验的单证哪几项是无效的。( )

单项选择题We are pleased to place with you an order for the following items on the that ______ they will be supplied from current stock.