解题思路： 感谢信的写作主要分以下三个部分。首先开头要明确的对对方提供的帮助或赠送的礼品表示谢意。主体部分则需列举对方提供的帮助，说明该帮助所起的作用等。结尾部分需再次表达诚挚的谢意并问候对方。
解题过程：
参考范文： Dear Mr Black,
I’m writing this letter to express my grateful thanks to you . During the friendly basketball watch, I fell down and sprained my ankle .Williams first put an ice pack on the ankle to reduce the swelling. Then he put a bandage over the wound and then press on it.Thanks to Williams’ first aid ,I was well soon . We miss you and wish you a happy life . I hope you and Williams know how I appreciate your hospitality and your many kindnesses to me.
Thank you for your kindness again and we are looking forward to seeing you again.
Yours，
Li Hua
