During international trade trasactions, the buyers and the sellers often bargin with each other in the form of commercial letters. And the writing ability of commercial letters directly affect the buyers' assessment to the counterparts' company.Commercial letters,no matter it's a letter, mail or fax, represent the image of your company and reveals your company's level and power.Therefore, the writing ability of commercial letters determines if one can conduct effective communication with the buyer in a professional approach and it holds the balance upon transactions in international trade.