I'm sorry. For these large orders, we insist on payment by L C.
对不起。对于这样金额大的订单,我们坚持用信用证支付。
Provided you can offer favorable quotations and guarantee delivery within four weeks from receipt of order, we will place regular orders with you.
贵方若能报优惠价并保证在收到定单后4周内交货,我方将定期订购。