【答案解析】Dear Aunt Liu,
It is a great pleasure to extend my sincere gratitude to you for your considerate and warm treatment when I was in Nanjing during the May Day holiday.
Before I went to Nanjing, I had booked a room in a hotel. But when I called on you, as was asked by my mother, you insisted that I stay in your house during the holiday. What"s more, you asked your daughter to accompany me when I visited the interesting places in Nanjing, which really added to the convenience and joy of the trip. Above all, every day when I finished my sightseeing, you had prepared a big meal for me.
What a good time I had in Nanjing! My heart-felt thanks are beyond words. I wish I would have the chance to pay you back for all your kindness.
With warmest regards.

Yours faithfully,
Li Ling