（2008·四川文综非延考区32）美国、日本和德国都是当今世界的发达资本主义国家，但美国实行总统制共和制，日本实行君主立宪制，德国实行议会制共和制。这表明                                 (    )①同一国体可以采取不同的政权组织形式　②一国采取什么政体与国家的性质无关　③国家政权组织形式有 其相对独立性  ④国体确定后采取什么政体并不重要

达尔文进化论告诉我们，很多动物为了适应自身生存的环境，进行出了符合一定物理规律的身体部位．以下事例从物理学的角度给出的解释中正确的是（　　）

甲、乙两个化工厂分布在如图所示的位置，箭头所指为工厂排水渠中水流方向。如果在a处取得的水样经化验只含有NaOH和Na₂SO₄；调整两厂废水流量，在c处取得的水样其外观是红褐色浑浊，经化验，溶液中溶质只含有NaCl，则b处取得的水样所含物质是（  ）

法国艾德拍卖行于2012年12月17日拍卖了一枚中国清朝乾隆玉玺，被一名身份神秘的电话竟拍者以112万欧元的价格拍走。关于该国宝怎样流出国门众说纷纭，下列说法最可信的是（    ）

阅读理解
    According to a recent survey, British teenagers are not in good health because they don't have enough time for sleep. They don't sleep well, either. They are often disturbed(打扰) by electronic gadgets(器具，装置) in their bedrooms. We call such kind of sleep “junk sleep”.
    We did a survey among 1,000 students aged 12 to 16, and we found out that 30 percent of them slept for only 4 to 7 hours a day. Nearly a quarter said they fell asleep while they were watching TV, listening to music or using other electronic gadgets.'
    Nowadays, almost all the teenagers have a phone, music system or TV in his or her bedroom. Almost 20 percent of the teenager boys said the quality of their sleep were not good. It was affected by leaving their TVs or computers on. The survey also found out that 40 percent of young people felt tired every day. What's more, the girls aged 15 to 16 felt the worst among them.
    “Teenagers need to realize the importance of sleeping well. If they sleep well, they will be able to study hard and perform well at school. I am shocked to know that so few teenagers have noticed the close connection between sleep and schoolwork,” said Dr Chris.