Dear______,
Iamwritingtoextendmysinceregratitudefor__________________(感谢的原因).Ifithadnotbeenforyourassistancein__________________(对方给你的具体帮助),IfearthatIwouldhavebeen___________________(没有对方帮助时的后果).
Noonewoulddisagreethatitwasyouwho___________________(给出细节).
Again,Iwouldliketoexpressmywarmthankstoyou!Pleaseacceptmygratitude.Bestwishes.
Yourssincerely,
LiMing