第一部分：表示感谢

Thank you so much for …

I warmly appreciate your hospitality（款待） .

I am writing to express my thanks for …

I am writing to extend mysincere/hearty gratitude/appreciation（真诚的感谢）for …

I would like to convey in this letter my heartfelt thanks to you for …

第二部分：说明事由

Thank you very much for the gift you sent me . It's one of the most wonderful gifts I got on my birthday .

I am writing this letter to thank you for your warm hospitality accorded to me and my delegation during our recent visit to your beautiful country .

I would also like to thank you for your interesting discussion with me which I have found very informative and useful .

第三部分：再次表示感谢

Thanks again .

Again , I would like to express my warm thanks to you ! Please accept my gratitude .

Thanks again and I hope that I will have the opportunity to return / repay your kindness .

I am looking forward to …