[解析]
Dear Jim,
I'm writing to tell you my exciting plan for the summer holiday.I want to join a Dragon Boat Training Camp,organised by our community.(高级句型)I wonder if you'd like to go with me.(训练营内容)
This camp lasting half a month will kick off on July 8th and we are expected to train about 3 hours every day on a small river flowing through our city.Whoever likes this sport is welcome with no age limit.(高级句型)As you know,it offers teenagers like you and me a chance to enjoy sports as well as building up our strength and character.(高级句型)Besides,we are bound to learn a lot behind the Dragon Boat Festival.If you are interested in it,let me know and I'll send you more information.(参加原因)
Hope to meet you at the training camp this summer.(询问意向)
Yours,
Li Hua