支付条款在函电中的拟定 — 国际贸易填空题
题目
某出口公司与买方签订合同，约定采用跟单托收中的付款交单（D/P）方式结算。业务员在函电中需将支付条款补全为："Payment shall be made by D/P at ____ days after sight for 100% of the invoice value, the shipping documents to be released against payment only." 若合同同时规定买方须在见票后30天付款，且发票总值为USD 80,000，则该条款空格处应填入的数字为____，而"against payment only"表明卖方在买方付款____（前/后）才交出单据。