求翻译：买方应通过买卖双方都接受的第一流银行向卖方开出以卖方为受益人的不可撤消金额，应包括100%发票金额。，可转让的即期付款信用证并注明不可转船。信用证必须在装船前40天开到卖方，信用证有效期限延至装运日期后21天在中国到期。是什么意思？

The buyer should be accepted by both buyers and sellers of first-class banks out to the seller to the seller as the beneficiary of an irrevocable amount should include 100% of the invoiced amount. , Transferable letter of credit payable at sight and indicate not to ship. Letter of credit must be ope

Buyer shall be accepted by the seller through the first-class banking to the seller issuing to the seller for the benefit of an irrevocable amount invoiced amount, they should include 100 per cent. Payment may be transferred, and indicate that letters may not be transferred to boat. pre-shipment cre

The buyer should the first-class bank which both accepts through the round turns start out to the seller take the seller cannot abolish the amount as the beneficiary, should include 100% invoice amount.Rotatable lets the immediate payment letter of credit and indicates cannot change ships.The letter

First-rate banks by buyers and sellers are accepted by the buyer to the seller out of the seller for the amount of irrevocable beneficiary should include 100% the invoice amount. , Sight payment letter of credit that can be transferred for security, is not available to ship. Letter of credit must be

First-rate banks by buyers and sellers are accepted by the buyer to the seller out of the seller for the amount of irrevocable beneficiary should include 100% the invoice amount. , Negotiable at sight credit and indicate non-transhipment. Letter of credit must be open to the seller prior to shipment