公共英语五级阅读文章

　　备考公共英语五级需要一定的阅读量，以扩充自己的词汇量与英语知识。下面为大家提供两篇优秀的公共英语五级阅读文章。

公共英语五级阅读文章

　　公共英语五级阅读文章一

　　Evolution and Wheels

　　In the past, evolutionary biologists contemplating the absence of wheels in nature agreed that the explanation was not undesirability: wheels would be good for animals, just as they are for us. Animals were prevented from evolving wheels, the biologists reasoned, by the following dilemma: living cells in an animal's body are connected to the heart by blood vessels, and to the brain by nerves. Because a rotating joint is essential to a wheel, a wheel made of living cells would twist its artery vein and nerve connections at the first revolution, making living impracticable. However, there is a flaw in the argument that the evolution of wheeled animals was thwarted by the insoluble joint problem. The theory fails to explain why animals have not evolved wheels of dead tissue with no need for arteries and nerves. Countless animals, including us, bear external structures without blood supply or nerves - for example, our hair and fingernails, or the scales, claws, and ho rns of other animals. Why have rats not evolved bony wheels, similar to roller skates?Paws might be more useful than wheels in some situations, but cats' claws are retractable: why not retractable wheels?We thus arrive at the serious biological paradox flippantly termed the RRR dilemma: nature's failure to produce rats with retractable roller skates.

　　进化与轮子

　　从前，研究自然界没有轮子的进化论生物学家都同意不能用无此需要来解释这种现象：轮子对于动物会像对于我们人类一样有好处。生物学家们推论，动物没有进化出轮子是由下述困难所致：动物身上的活细胞通过血管与心脏相连，通过神经与大脑相连。因为一个旋转的接头对轮子来说是至关重要的，由活的细胞构成的轮子在第一次转动时便会扭伤其上的动脉和神经的连结，因而不现实。

　　不过，动物未能进化出轮子是受阻于无法解决接头问题的说法有一个缺陷。这种理论无法解释为何动物没有进化出由死组织构成的而无需动脉和神经的`轮子。包括人在内的无数动物都有一些没有血液供应和神经的体外构造，例如，我们的头发和指甲，或者鳞片、爪子和其它一些动物的角。为什么老鼠没有进化出类似于滑轮溜冰鞋的骨质的轮子呢?在某些情况下，爪子可能比轮子更有用，但猫的爪子是可以伸缩的：为什么不能有可以伸缩的轮子呢?这样，我们便得出了一个被戏称为 RRR 的严肃的生物学悖论：大自然未能产生出有可伸缩的滑轮溜冰鞋的老鼠。

　　公共英语五级阅读文章二

　　Population Growth

　　The growth of population during the past few centuries is no proof that population will continue to grow straight upward toward infinity and doom. On the contrary, demographic history offers evidence that population growth has not been at all constant. According to paleoecologist Edward Deevey, the past million years show three momentous changes. The first, a rapid increase in population around one m illion B. C., followed the innovations of tool making and tool using. But when the new power from the use of tools has been exploited, the rate of world population growth fell and became almost stable. The next rapid jump in population started perhaps 10,000 years ago, when mankind began to keep herds, plow and plant the earth. Once again when initial productivity gains had been absorbed, the rate of population growth abated. These two episodes suggest that the third great change, the present rapid growth, which began in the West between 250 and 350 years ago, may also slow down when, or if, technology begins to yield fewer innovations. Of course, the current knowledge revolution may continue without foreseeable end. Either way - contrary to popular belief in constant geometric growth - population can be expected in the long run to adjust to productivity. And when one takes this view, population growth is seen to represent economic progress and human triumph rather than social failure.

　　人口增长

　　以往几个世纪人口的增长并不能证明人口会无限地直线向上增长直到毁灭的地步。相反地，人口统计史料证明人口的增长完全不是稳定的。古生态学家爱德华·狄维认为，在过去100 万年间出现过3 次重大的变动。第一次在公元前 100 万年左右，随着在工具的制作和使用上的革新而出现人口迅速增长。但当工具的使用所产生的新动力被充分利用以后，世界人口增长率下降并且趋于稳定。第二次人口剧增大约始于人类开始蓄畜、垦耕的10，000 年前。一旦最初的生产力增长被吸收殆尽，人口的增长再次衰落。以上两段说明，若技术革新的成果开始减少，从250 到350 年前就在西方开始出现的并且目前还在继续的人口迅速增长可能也会放慢。当然，当前的知识革命也许会持续下去而无法预见其末来。无论如何，与那种认为人口以几何级数持续增长的观点相反，从长远的观点来说，人口可望受到生产力的调节。接受了这一观点，人口的增长就可以被看成是经济进步和人类胜利的标志，而不是社会衰败的标志。

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