You have just returned from a visit to a university in Great Britain. And you were warmly treated there by Professor Smith. Please write a letter to express your thanks to him for his hospitality.
Dear Prof. Smith,
I am writing to extend my sincere gratitude to you. I am referring to your warm treatment in Great Britain.
When I arrived in Oxford University, it was you who introduced so many of famous professors and celebrated scholars at your University to me. You also invited me to your home and treated me with delicious food. If it had not been for your assistance, I fear that I would not have had such a pleasant stay in Great Britain. My appreciation to your selfless help is beyond any words.
I sincerely hope that I can repay your kindness in the near future. Once again, please accept my heartfelt gratitude. I am looking forward to your reply.