There are few families in the United States that do not have either a radio or television set. Both of them have become a necessary part of our daily life, keeping us filled with the news of the day, teaching us in many fields of interest, and making us happy with singing, dancing and acting.
Marconl, the Italian inventor, who gave us the radio, probably didn't know how much his great invention would have done for the world in the years to come. Radio had, perhaps done as much as any other communication tool. Things of the world can be reported to people everywhere a few seconds after they happen. Travelers in or out of–the–way places, ships at sea even astronauts round the earth are able to keep in touch with each other by radio.
Television is another important invention. It lets us see as well as hear the actor. Since its appearance, TV has done a great deal in the daily life of people everywhere. Many programs are now televised in color.
Perhaps the most modern invention is “Telstar”, a “star” moving round the earth. It makes it possible for the people all over the world to be closer than ever before. Now a family in Chicago can watch on TV a motor–car race in Italy, a table tennis competition in Beijing or a volleyball match in Japan as these events are actually happening!
≈1.910， 
≈6.042，则 
≈