商品的描述是发票的主要内容，《UCP500》对其有什么规定?
InthepracticeofL/Ctransaction,thebuyerisnotrequiredtopayforthegoodsuntilthearrivaloftherelevant____.
托收指示书的主要内容有（）
Underthevechartering，theshipownerisresponsibleforthefixedrunningexpensesaswellasfortheveexpenses.
Themarinecargoinsurancepremiumratesmayvarydependingonfactorssuchas（）.
