假设你是李华，于2010年6月3日搭乘国外某航空公司航班(flight number BA793)回国后，发现遗失了一个行李箱(suitcase)。现请用英文给该航空公司写一封信，请他们帮你寻找。信件要点包括:陈述写信原因，简要描述该行李，说明其重要性，期待回复并表示感谢。

　　【参考范文】

　　Dear Sir/Madam ,

　　I am very sorry to say that I left my suitcase in flight number BA793 on 3 rd , June , so I am writing this letter to ask you for help .The lost suitcase is a red one with a long handle . It is of great importance to me . In it are some valuable books and my credit cards . I will be very grateful if anyone of you contact me by telephone immediately after seeing it . My telephone number is 133456 . There is nothing more gratifying to me than your reply .

　　I am looking forward to your reply .

　　Yours truly,

　　Li Hua