问题
多项选择题
根据《工业管道的基本识别色、识别符号和安全标识》GB7231-2003国家标准，工业管道的识别符号由（）组成。
A.使用性能
B.物质名称
C.介质流向
D.工艺参数
E.安全图例
答案
参考答案：B, C, D
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根据《工业管道的基本识别色、识别符号和安全标识》GB7231-2003国家标准，工业管道的识别符号由（）组成。
A.使用性能
B.物质名称
C.介质流向
D.工艺参数
E.安全图例
参考答案：B, C, D
A new study suggests that the more teenagers watch television, the more likely they are to develop depression (抑郁症) as young adults. The researchers used a national long-term survey of healthy young teenagers of about 13—16 to find out the relationship between media(媒体) use and depression. They based their findings on more than 4000 young teenagers who were not depressed when the survey began in 1995. As part of the survey, the young people were asked how many hours of television or videos they watched daily. They were also asked how often they played computer games and listened to the radio. Here was the result. The young people spent five and a half hours a day using media and more than 2 hours of that was spent watching TV. Seven years later, in 2001, more than 7% of the young people had signs of depression. The average age at that time was 21. Brian Primack at the University of Pittsburgh medical school was the lead author of the new study. He says every extra hour of television meant an 8% increase in the chances of developing signs of depression. The researchers say they did not find any such relationship with the use of other media such as movies, video games or radio. But the study did find that young men were more likely than young women to develop depression given the same amount of media use. Doctor Primack says the study did not find out if watching TV causes depression directly. But one possibility, he says, is that it may take time away from activities that could help prevent depression, like sports and social activities. It might also prevent a person from sleeping well, he says, and that could have an influence. The study was just published in the Archives of General Psychiatry. In December, the journal Social Indicators Research published a study of activities that help lead to happy lives. Researchers from the University of Maryland found that people who describe themselves as happy spend less time watching television than unhappy people. The study found that happy people are more likely to be socially active, to read, attend social services and to vote.
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