推薦答案To whom it may concern,
I'm XXX and I'm writing this email to thank for your important recommendation letter of me, which finally granted me the opportunity for my graduate study in XXX University.
I have been told that your letter gave great credit for my application of the graduate study and the final admission. I want to sincerely thank you for your previous recommendation letter and I really appreciate all your help during my application.
Thank you very much again and please keep in touch.
Best wishes.
Sincerely,
XXX