发明
On invention
The 20th century was an age of great inventions and discoveries, which revolutionized human life. The invention and popularization of the computer dramatically changed almost every aspect of people’s life and work. The invention of television and other appliances., such the VCD, DVD, hi-fi, Walkman, MP3 and MP4, offers human beings more and better visual and audio enjoyments. There is no denying that we live much better than before. However, a double-edged sword of good and evil has hung over human technology for the beginning. We are more and more aware that some scientific or technological advances, though useful, may have unpleasant side effects. The small machine, the Walkman, is no exception. It is, on the one hand, a handy personal stereo that can accompany us wherever we go, but on the other, it may damage our hearing and even bring risks to our lives if used inappropriately