【正确答案】[参考范文]
Dear David，
I'm glad to know that you are going to teach English in Beijing．
As the capital，Beijing is a city with a long history．Though it lies in the north of China，it is very hot in summer．In winter，of course，it is cold．Autumn is the best season while spring is short and windy．The transportation here is convenient although sometimes it’s not fast．You can choose buses，subways，taxes or bikes as you like．The food is delicious and not very expensive．There are kinds of native restaurants，and you can find west restaurants such as KFC’s and McDonald’s at the same time．I believe you’ll have a wonderful time here．
Looking forward to hearing from you soon．