假定你是李华，你的美国朋友Jack来信说，他暑假后将到北京大学留学。请你根据以下内容给他写一封回信，告知相关情况。
1.简单介绍北京大学；
2.简单介绍北京（例如生活便利，居民友善等）；
3.留学期间愿意提供任何帮助。
注意：1.词数100左右：2.可以适当增加细节，以使行文连贯。
Dear Jack,
I am glad to know that you will come to China for further study. Now let me tell you what you are concerned with.
As is known to us, Peking University is considered to be one of the top universities in China, which is famous fo
