About fifty years ago, when television first came out, people thought that radio was no longer useful. Television has both sounds and images . It is much more real and interesting to watch television than to listen to the radio. However, fifty years later radio is still very popular and it will be here for a long time. One reason is that we don't need to see an image when we listen to the music on the radio. In fact, listening with your eyes closed is the best way to listen to a piece of music. You can imagine yourself on a sandy beach or up high on a mountain. In other words, you can create your own images. Moreover, while listening to the radio, you don't have to take your eyes off your work. For example, you can listen to the radio and drive at the same time. Or you can read a book and listen to the radio. Television, on the other hand, doesn't have this advantage. A radio is much smaller than a television. You can take a radio anywhere and turn it on anytime you want. In a quiet place you can use headphones to listen to the news or music on the radio. In this way you won't disturb anybody. Moreover, a radio is much cheaper than a television. For less than $ 20 you can buy a small radio and have fun with it. What is the passage mainly about?
Music. Radio. Sound. Television.