题干

随着农业投入的不断加大,曾经在我国工业领域出现的严重趋同的现象在农业领域也逐渐“升温”:听说某地种辣椒赚钱,许多地方就一哄而上;看到某地种草能致富,就有人指挥农民把庄稼砍了,种上草……大量重复的农产品就像同类工业品一样,产品效益大幅降低。这说明
①单纯的市场调节具有自发性、盲目性、滞后性    
②发展市场经济离不开国家的宏观调控 
③必须削弱政府管理经济的职能                  
④市场经济要健康发展就必须完全制止重复建设

A:②

B:①②

C:①②④

D:①②③④

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答案(点此获取答案解析)

B

同类题2

阅读下列文段,完成后面练习题:

    彗星主要是由冰构成的──水(H2O)冰,还有少量的甲烷(CH4)冰和一些氨(NH3)冰。在撞击地球的大气层时,一个中等大小的彗星碎片会产生一个白炽的火球和一种巨大的冲击波。火球会烧毁树木,冲击波会扫平森林,它的声音还会波及全球。但是这样的彗星不太可能在地上撞出一个环形山。彗星上的冰块在进人大气层的时候全部融化了,因此不会幽灵般地出现,这种现象令人不安地向人们关于宇宙是万古不变、井然有序这一观念进行挑战。如果那条天天随着星星起落的壮丽的乳白色光带是无缘无故地出现在那里,与人间世事毫无关系,那简直是不可思议的。因此出现了这样的观点:彗星是灾难的预兆,是神谴的预兆──它们预示了帝王的终日,王国的崩溃。对于彗星,巴比伦人认为是天髯,希腊人认为是垂发,阿拉伯人认为是燃烧的剑。在托勒密时代,人们根据彗星的形状把它们分类为“梁”、“喇叭”。“坛子”等。托勒密认为彗星给人类带来战争、炎热的气候和“动乱”。中世纪的一些彗星图看上去像未探明的飞行的十字架。一个名叫安德烈亚斯·西利奇厄斯的马格迪堡路德教主管人(即主教),在1578年发表了一篇题为“新彗星的科学启示”的文章。他在文章中。提出了一个独特的观点,他说彗星是“人类罪恶的浓烟,每天、每时、每刻都在升腾,它在上帝面前丑态百出、胆战心惊,逐渐地由浓烟形成长着卷发梳着辫子的彗星,最后被天国最高法官的怒火烧着了”。但是另一些人反驳说,如果彗星是罪恶的浓烟的话,天空势必乌烟滚滚。


                                                                                                          ──选自《宇宙的边疆》(第四章)

同类题5

    Yang Nan, 17, was happy to move to her new home in a northern area of Beijing. She was told that her neighborhood used to be rich farmland planted with vegetables, corn and wheat. But looking at the new road, beautiful parks and supermarkets, to her surprise, Yang couldn't see any sign that food was once grown there.
    Yang is not alone. In recent years, many Chinese people have moved into new houses in country areas. Tall buildings have been built everywhere in the suburbs. The crops and fruit trees are no more grown there. But these changes have caused big problems too, warns Gan Zangchun, an official(官员)at the Ministry of Land and Resources(国土资源部).
    "Chinese cities are growing very fast. This has made the area for farmland much smaller than before. This is really bad for the country's ability to grow food, not to mention the lives of farmers," said Gan last Monday.
    As the population of China is growing all the time, the country needs more farmland to grow food for the increasing people of China. But the recent rise in house prices has made selling land a good business. A lot of land has been used to build new houses for sale. So you can see, the shortage of the farmland is now a very serious problem.
    Pollution, such as, oil pollution, industrial(工业) pollution and water pollution, which makes land useless, is another reason for the big drop in China's farmland. About 2.67 million square kilometers of land in China have been polluted and turned into desert.
    Today, can we use less farmland to grow enough food for more people? Of course not! The government wants China to have at least 120 million hectares(公顷) of farmland. Only in this way can we raise such a big population. But there are only about 121.8 million hectares left. "It will be really difficult to reach the goal", Gan said. He said that the government would fight illegal(非法的) land use and something useful must be done to stop farmland from becoming desert.