As a result, the population of the world is increasing, causing tots of problems. Second, because of the development of industry, tots of the wastes from factories pour into the air and rivers, causing pollution of att kinds. Third, some terrorists are using science and technology against mankind. They use biological, chemical and unclear weapons to threaten world peace...

　　So its urgent that we find ways to solve these problems. But we should not stop the development of science and technology because of these disasters they bring, just as we should not give up eating for fear of choking. In addition, we should make some rules to regulate our actions. As long as we use science and technology in a proper way, they may bring us even more benefits.