Thank you for one of the most memorable days of my trip.
為了旅途中最值得紀念的一天，謹向您表示感謝。
Thank you for one of the most enjoyable visits we have had in many months/ for some time.
在您處的'參觀訪問，是我們幾個月（一段時間）中最愉快的一天。謹向您表示感謝。
Thank you for doing so much to make my trip to New York interesting/ pleasant / fruitful.
為了使我去紐約的旅遊有趣（愉快）（大有收穫），您做了許多事，特此致謝。
Thank you so much for your generous hospitality.
非常感謝您慷慨的款待。
I hope something will bring you to New York soon， so that I can return/ reciprocate your kindness/ hospitality.
希望不久您能有機會到紐約來，使我能答謝您的盛情款待。
You must give me an opportunity to return your kindness when you visit my home.
希望您光臨我處，使我能答謝您的盛情。
Thank you very much indeed / ever so much/ so much.
最真誠地（確實）（非常）感謝您。
Many thanks for your kind/ warm letter.
