请将下列英文翻译为中文,并指出其含义。 (1)The buyer shall pay 10% of the sales proceeds in advance by T/t within 10 days after the signing of the contract and open through a bank acceptable to the seller an Irrevocable Letter of Credit payable at sight for 90% of the sales proceeds to reach the seller by the end of January 2010 valid for negotiation in China until the 15 day after the date of shipment. (2)The buyers shall duly accept the documentary draft drawn by the sellers at 30 days af ter date of B/L upon first presentation and make payment on its maturity.The shipping documents are to be delivered against payment only.