Dear _______，

         Thank you very much for/Thanks a lot for/Many thanks for _________ /I’m writing to you about my gratitude for ________ /I’m very grateful to you for ________ .(开门见山地交代感谢原因)

        But for/Without your help，________ .(从反面衬托对方的作用)/It’s very kind of you to ________.(从正面说明对方的作用)

         I hope to have the opportunity to express my gratitude to you/repay your kindness. I will feel very honored and pleased if  ________ .(提出回报对方的方式)Would you please let me know ?(希望对方给予回应)Thank you again for what you have done.(再次表达感谢)

                                                                    Yours sincerely,

                                                                        ________