what is confimed and unconfired letters of credit?

what is confimed and unconfired letters of credit? the accurate quantity will be informed and ask you pick it up when it is confimed请问此句正确的理解! What is five and five? what is five and two? What is five and tow? What is five and three? what is one and one? what is twelve and fourteen What is one and one? What is nine and thirteen what is relationship she and What is eleven and thiry? and what is your name? what is forever and ever what is capital and reserves? What is Trick and Treat? What is Houyhnhnms and yahoos? what is 6and 这里的and