单选题   A new study suggests that the more teenagers watch television, the more likely they are to develop depression as young adults. But the extent to which TV may or may not be to blame is a question that the study leaves unanswered.
    The researchers used a national long-term survey of adolescent health to investigate the relationship between media use and depression. They based their findings on more than 4,000 adolescents 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.
    Media use totaled an average of 5 and one-half hours a day. More than 2 hours of that was spent watching TV.
    7 years later, in 2002, more than 7 percent 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 percent 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 explore why watching TV causes depression. But one possibility, he says, is that it may take time away from activities that could help prevent depression, like sports and socializing. It might also interfere with sleep, 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. Sociologists 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 religious services and to vote.
单选题     According to the first paragraph, what remains unsolved in the new study?
 
【正确答案】 B
【答案解析】第1段最后一句开头的the extent表明电视在“多大程度上”导致青少年患上抑郁症这一问题上答案尚未明朗，也就是说，电视“如何”使青少年患上抑郁症这一问题尚需进一步的研究，因此，本题应选B。
单选题     The more than 4,000 adolescents were chosen as the subjects of the study because they ______.
 
【正确答案】 A
【答案解析】第2段最后一句中的定语从句表明这些年轻人成为调查对象时都没有抑郁症，而这也是本文中唯一一处提到选择受试者标准的地方，因此，本题应选A。
单选题     What can be inferred from the seventh paragraph?
 
【正确答案】 C
【答案解析】第7段第1句中的such relationship指的是第6段最后一句提到的看电视的时间和患抑郁症的概率之间的关系，由此看来，第7段第1句应暗示使用电视以外的媒体的时间长短与患抑郁症的概率不形成同样的正比关系，C说的正是这个内容，因此本题应选C。
单选题     In the last sentence of the eighth paragraph, 'It' refers to ______.
 
【正确答案】 B
【答案解析】第8段最后一句中的also表明该句中的代词It和上一句中的代词it所指相同，而根据该段的第1句可以推断第2句中的it应指watching TV，由此可见，本题应选B。
单选题     The study done by the sociologists from the University of Maryland was mainly intended to ______.
 
【正确答案】 D
【答案解析】最后一段第1句中的a study指的就是下一句提到的Sociologists from the University of Maryland所做的研究，第1句末尾的定语从句表明了该研究的目的是为了帮助人们更快乐地生活，对比之下可见D表达了与该定语从句意思相近的内容，因此本题应选D。