Dear ____,
　　I'm glad to have received your letter and I'm writing to invite you to join us in a trip this Sunday morning.The destination is the Green Island which is located south of the Ming Mountain.At 8:00 am on January 12th,we will gather at the Times Square and set off for the Island at 8:10 am.Make sure that you get on the bus on time and bring your sleeping-bags because we are going to spend the night in the open air.After we arrive on the Island,we will go mountain climbing.Remember to bring your own camera so that you can take some good photos.In the evening after watching the sunset we will put up tents at the foot of the mountain and cook over a camp fire.I'm sure we will have great fun!
　　Looking forward to your reply.
　　Yours,
　　_________