Dear Cheng Wei,
I am very glad to know that you will get a chance to study in London for a year.I would like to tell you something about London so that you can have some ideas about it before you come.
About studies,the middle school you'll study in is well-known in the local place.By communicating with your teachers as well as your classmates frequently,you can improve you English level at a high speed.And the key to deal with you life problem is that you can choose a host family.Eating and Staying with them can help you know about the habits and customs the Englands have better.In your spare time,you can travel around the places of interest in London,such as the Thames and the Eyes of London.But there's also a big problem in London that the traffic is busy.It's possible that you'll have to face the traffic jam every single day.
I look forward to seeing you in London soon and I hope you can have a cozy life here.
Best regards,
Jack