【正确答案】
Dear Colleague,
   We invite you to attend an international symposium on city garbage disposal to be held in Shanghai, in September, 2009. The symposium is jointly sponsored by the Environment Institute of China and the Shanghai Municipal Government.
   The disposal of city garbage is an issue of major concern for every city in the world. Thus, it is necessary for people to exchange their views on the latest development of garbage disposal and work out some effective ways for the issue.
   The aim of the symposium is to contribute significantly to the healthy environment in cities. We hope that you will find topics of your interest and submit an abstract describing recent research on any aspect concerning city garbage disposal. We are looking forward to seeing you in Shanghai. Sincerely yours,
                                                                               Zhang Tian
                                                                                  Director
                                                           Environment Institute of China