1. The Buyers shall open through a bank acceptable to the Sellers an Irrevocable Sight Letter of Credit to reach the Sellers 30 days before the month of shipment, valid for negotiation in China until the 15th day after the month of shipment.
我自己翻译的是：买家应该在卖家许可的银行内开设不可撤消的信用证,并且在30天内给卖家．．．（后面的有点翻译不过来～）
2. Since the premium varies with the scope of insurance,extra premium is for buyer’s account,should additional risks be covered.
我自己翻译的是：因为保险金不在保险的范围之内，额外的保险金是为客户的帐户准备的，并且也要附加上额外的风险。
（不知道是不是对的～）