Dear ______,
How about your life/ study/ work? I'm writing to express my thanks for your _____(感谢的原因). If it had not been your assistance in _____(对方给你的具体帮助), I fear that I would have been_____ (没有对方帮助时的后果).
During the ______, you gave me generous help and continuous guidance by _____. First, you _____.What's more, you ______. There is still one thing that I can't forget. That is _______. (原因)
Thanks a lot for your kindness again. (再次致谢)
Give my best regards to ______. (祝愿)
Yours sincerely
_______