翻译下列句子,体会商务英语的语言特点。 (1) Our terms of payment are by confirmed, irrevocable letter of credit, without recourse, payable at sight against presentation of shipping documents to the negotiating bank at the port of shipment. (2) The policy is being prepared accordingly and will be forwarded to you by the end of the week together with our debit note for the premium. (3) The contract shall be valid for 10 years from the effective date of the contract, on the expiry of the validity term of contract, the contract shall automatically become null and void. (4) An insurance claim should be submitted to the Insurance Company or its agent as promptly as possible so as to provide the latter with ample time to pursue recovery from the relative party in fault. (5) Please be informed that, on account of the fluctuations of foreign exchange, the quotation is subject to change without previous notice.