【答案解析】

21st century is a century of the Internet. The Internet is an information bridge, which bridges up cultural differences and narrows down geographic distance.
Life on the Net is colorful The latest news can reach you in the shortest time. Either sports events or beauty competitions can be viewed live without an entrance ticket. You can also do shopping through the Internet. On the other hand, the Internet is a powerful tool for communication. E-mail has become the most convenient and the cheapest way to communicate with your friends and to get to know new friends. In addition, online education is popular, for people can have more freedom to choose their learning program with the help of the Net.
Nevertheless, life on the Net is only a part of our life. Surfing the Internet may enrich your life. But too much Sitting in front of computer and lack of sports can be harmful to your health. If you want to keep health, please go outdoors with your friends for more fresh air and sunshine.