2.参考词汇:学生会和团委the Young League and Student's Union;
One possible version:
In order to support Beijing to hold the 2008 Olympic Games and protect our environment, an activity was organized by the Young League and Student's Union of our school during the week from June 3rd to June 8th.
All the students in the senior grades took active part in it. Some students cleaned the playground, watered the young trees and flowers, and removed weeds. Some students collected waste paper, old books, empty cans and old toys. They had them sorted and sent them to the recycling center.
The activity is really instructive. Now we all have realized how important protecting the environment is.