单选题设A是3阶方阵，将矩阵A的第1列与第2列交换得到矩阵B，再把矩阵B的第2列加到第3列得矩阵C，则满足AQ=C的可逆矩阵Q为______．A．B．C．D．

单选题产权明晰化的含义是____________。 　　①产权的排他性 ②产权的可分割性或可分离性 ③产权的不可分割性 　　④法人财产权的独立化 ⑤产权的可转让性 ⑥产权的有效保护

单选题由于量子理论的结论违反直观，有些科学家对这一理论持不同看法。尽管他们试图严格地表明量子理论的断言是不精确的(试图严格地证伪它)，但是发现，其误差在通常可接受的统计范围之内。量子理论的这些结果不同于与它相竞争的理论的结果，这表明接受量子理论是合理的。 以下哪一项原则最有助于表明上述推理的合理性?

单选题某设备的原始价值为8000元，初始运行费用为400元，每年低劣化增加值为320元，残值为0，则该设备的最优更新期（经济寿命）约为（ ）

单选题马克思主义政治经济学的分析从（ ）开始的。

单选题设f(x)是连续的偶函数，则其原函数F(x)一定是______．

单选题如果灵活性偏好曲线接近水平，意味着（ ）

单选题营养学家说，宣传任何一种保健品能治病都是骗人的。但是，对于饮食不规律的人群来说，服用某些保健品是必要的。 如果接受该营养学家的看法，则必须接受以下哪一项陈述?

单选题当两种商品X、Y的效用函敦为Y(X．Y)=XY时，下列哪一种效用函数描述了相同的偏好次序?

单选题在一次魔术表演中，从七位魔术师G、H、K、L、N、P和Q中选择六位上场表演，表演时分成两队：1队和2队。每队有前、中、后三个位置，上场的魔术师恰好每人占一个位置，魔术师的选择和位置安排必须符合下列条件： (1)如果安排G或H上场，他们必须在前位； (2)如果安排K上场，他必须在中位； (3)如果安排L上场，他必须在1队； (4)P和K都不能与N在同一个队； (5)P不能与Q在同一个队； (6)如果H在2队，则Q在l队的中位。

单选题Every second, 1 hectare of the world's rainforest is destroyed. That's equivalent to two football fields. An area the size of New York City is lost every day. In a year, that adds up to 31 million hectares—more than the land area of Poland. This alarming rate of destruction has serious consequences for the environment; scientists estimate, for example, that 137 species of plant, insect or animal become extinct every day due to logging. In British Columbia, where, since 1990, thirteen rainforest valleys have been clearcut, 142 species of salmon have already become extinct, and the habitats of grizzly bears, wolves and many other creatures are threatened. Logging, however, provides jobs, profits, taxes for the government and cheap products of all kinds for consumers, so the government is reluctant to restrict or control it. Much of Canada's forestry production goes towards making pulp and paper. According to the Canadian Pulp and Paper Association, Canada supplies 34% of the world's wood pulp and 49% of its newsprint paper. If these paper products could be produced in some other way, Canadian forests could be preserved. Recently, a possible alternative way of producing paper has been suggested by agriculturalists and environmentalists: a plant called hemp. Hemp has been cultivated by many cultures for thousands of years. It produces fiber which can be made into paper, fuel, oils, textiles, food, and rope. For many centuries, it was essential to the economies of many countries because it was used to make the ropes and cables used on sailing ships; colonial expansion and the establishment of a world wide trading network would not have been possible without hemp. Nowadays, ships' cables are usually made from wire or synthetic fibres, but scientists are now suggesting that the cultivation of hemp should be revived for the production of paper and pulp. According to its proponents, four times as much paper can be produced from land using hemp rather than trees, and many environmentalists believe that the large-scale cultivation of hemp could reduce the pressure on Canada's forests. However, there is a problem: hemp is illegal in many countries of the world. This plant, so useful for fiber, rope, oil, fuel and textiles, is a species of cannabis, related to the plant from which marijuana is produced. In the late 1930s, a movement to ban the drug marijuana began to gather force, resulting in the eventual banning of the cultivation not only of the plant used to produce the drug, but also of the commercial fiber-producing hemp plant. Although both George Washington and Thomas Jefferson grew hemp in large quantities on their own land, any American growing the plant today would soon find himself in prison—despite the fact that marijuana cannot be produced from the hemp plant, since it contains almost no THC (the active ingredient in the drug). In recent years, two major movements for legalization have been gathering strength. One group of activists believes that ALL cannabis should be legal—both the hemp plant and the marijuana plant—and that the use of the drug marijuana should not be an offense. They argue that marijuana is not dangerous or addictive, and that it is used by large numbers of people who are not criminals but productive members of society. They also point out that marijuana is less toxic than alcohol or tobacco. The other legalization movement is concerned only with the hemp plant used to produce fiber; this group wants to make it legal to cultivate the plant and sell the fiber for paper and pulp production. This second group has had a major triumph recently: in 1997, Canada legalized the farming of hemp for fiber. For the first time since 1938, hundreds of farmers are planting this crop, and soon we can expect to see pulp and paper produced from this new source.

单选题若某商品的需求曲线为一条向右下方倾斜的直线，当厂商由高到低逐渐降低销售价格时( )。

单选题赵亮：一个国家的经济要发展，人民要富裕，社会必须稳定。 王宜：你的断定不成立。我国的近邻老挝是一个被誉为世界上最舒适安宁的国家，很多后现代的西方人，都跑到老挝寻求前现代的安宁和舒适。但老挝是东南亚最穷的国家之一，人均GDP还不到300美元，约等于中国的1/10，比正在崛起的越南也差很多。 以下哪项对王宜的反驳的评价最为恰当?______

单选题某国家领导人要在连续6天(分别编号为第一天、第二天……第六天)内视察6座工厂F、G、H、J、O和R，每天只视察一座工厂，每座工厂只视察一次。视察时间的安排必须符合下列条件： (1)视察F在第一天或第六天。 (2)视察J的日子比视察Q的日子早。 (3)视察Q恰在视察R的前一天。 (4)如果视察G在第三天，则视察O在第五天。

单选题在某大型理发店内，所有的理发师都是北方人，所有的女员工都是南方人，所有的已婚者都是女员工，所以，所有的已婚者都不是理发师。 下面哪一项如果为真，将证明上述推理的前提至少有一个是假的?

单选题设f(x)在[-a，a]上连续且为偶函数，，则______．