Read the following passage:
(1) How does television affect our lives? It can be very helpful to people who carefully choose the shows that they watch. Television can increase our knowledge of the outside world; there are high quality programmes that help us understand many fields of study, science, medicine, the different arts and so on. Moreover, television benefits very old people, who can't leave the house, as well as patients in hospitals. It also offers non-native speakers the advantages of daily informal language practice. They can increase their vocabulary and practice listening.
(2) On the other hand, there are several serious disadvantages of television, of course, it provides us with a pleasant way to relax and spend our free time, but in some countries people watch television for an average of six hours or more a day. Many children stare at the TV screen for more hours a day than they spend on anything else, including studying and sleeping. It's clear that TV has a powerful influence on their lives and that its influence is often negative.
(3) Recent studies show that after only thirty seconds of television viewing, a person's brain 'relaxes' the same way that it does just before the person falls asleep. Another effect of television on the human brain is that it seems to cause poor concentration. Children who view a lot of television can often concentrate on a subject for only fifteen to twenty minutes. They can pay attention only for the amount of time between commercials.
(4) Another disadvantage is that television often causes people to become dissatisfied with their own lives. Real life does not seem so exciting to these people. To many people, television becomes more real than reality and their own lives seem boring. Also many people get upset or depressed when they can't solve problems in real life as quickly as television actors seem to.
(5) Before a child is fourteen years old, he or she views eleven thousand murders on the TV. He or she begins to believe that there is nothing strange about fights, killings, and other kinds of violence. Many studies show that people become more violent after viewing certain programmes. They may even do the things that they see in a violent show.