【答案解析】Dear Wang Yu,
   Congratulations to you on your promotion. I'm really happy for you!
   It has been almost a year and a half since you saw me off. I can still vividly recall the kindness you showed me. I remember you accompanied me to the railway station when I left. When the porters were slow to show up, you obligingly carried my suitcases, one after another, into the train. I will never forget these and thank you!
   As to your promotion, I do think you deserve it and I wish there were more than words to express my sense of admiration to you since you are the model of hard work. Congratulate you again, and wish you a greater success in the future.