仅供参考.
Dear Mr.and Mrs.White,
I'm writting this letter to thank you for your warmly hospitality accorded to me during my recent vistit in London.
During the stay in London,I was very happy with you and your family.I am looking forward to your vistit to China when I will be able to able to pay back some of the hospitality I received my memorable stay in your family.With personal regards.
Faithfully yours,
Wang Min