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题目： 问答题
试根据火花圆形及特征，在牌号中哪个是30＃钢。（提示：碳是引起火花爆裂的主要元素，随着含碳量的增加，花粉增多，亮度增加。
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- How does TV affect our lives? It can he 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 programs that help us understand many fields of study: science, medicine, the arts, and so on. Moreover, TV benefits very old people who can't often leave the house, as well as patients in hospitals. It also offers non-native speakers the advantage of daily informal language practice; they can increase their vocabulary and practice listening On the other hand, there are several serious disadvantages to TV. Of course, it provides us with a pleasant way to relax and spend our free time, but in some countries, people watch the TV for an average of six hours or more a day. Many children stare at a TV screen for more hours each day than they do anything else, including studying and sleeping It's clear that the TV has a powerful influence on their lives and that its influence is often negatk'e. Recent studies show that alter only thirty seconds of TV, a person' s brain 'relaxes" the same way that it does just before the person falls asleep. Another effect of TV on the human brain is that it seems to cause poor concentration. Children who view a lot of TV can often concentrate on a subject for only fifteen to twenty minutes; they can pay attention only for the amount of time between commercialsAnother disadvantage is that TV often causes people to become dissatisfied with their own lives. Real life does not seem as exciting to these people as the lives of actors on the screen. To many people, TV 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 TV actors seem to. On the screen, actors solve serious problems in a half-hour program or a thirty-second commercialBefore 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 certain programs. They may even do the things that they saw in a violent showThe most negative effect of the TV might be people's addiction to it. People often feel a strange and powerful need to watch TV even when they don't enjoy it. Addiction to a TV screen is similar to drug or alcohol addiction, people almost never believe they are addictedRead Passage and decide whether the following statements are True or False. Write T for True and F for False against the number of each of the statements on your Answer Sheet21. TV programs are definitely helpful to anyone22. There are positive as well as negative effects of TV on our lives23. TV can help improve one's foreign language24. Watching a lot of TV won't affect our concentration at all25. Some children spend more time watching TV than studying and sleeping26. The lives of people in TV shows seem to be very exciting27. TV programs can help people solve problems as quickly as the actors28. TV violence makes some people, especially children, take violence in real Life forgranted29. One of the symptoms of addiction to television is a strong desire to watch it even ifthe program is not interesting30. The passage mainly discusses the advantages of TV
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