小马备考包笔记、参考答案 8.doc

Meteorite Impact and Dinosaur ExtinctionParagraph 1: There is increasing evidence that the impacts of meteorites have had important effects on Earth, particularly in the field of biological evolution. Such impacts continue to pose a natural hazard to life on Earth. Twice in the twentieth century, large meteorite objects are known to have collided with Earth. 有越来越多的证据表明陨石的冲击会对地球产生重要影响，尤其是在生物进化领域。这样的冲击持续给地球生物造成危险。二十世纪曾有两次已知的陨石撞击地球事件。hazard hzd n.危险, 冒险, 危害 vt.冒险, 赌运气Paragraph 2: If an impact is large enough, it can disturb the environment of the entire Earth and cause an ecological catastrophe. The best-documented such impact took place 65 million years ago at the end of the Cretaceous period of geological history. This break in Earths history is marked by a mass extinction, when as many as half the species on the planet became extinct. While there are a dozen or more mass extinctions in the geological record, the Cretaceous mass extinction has always intrigued paleontologists because it marks the end of the age of the dinosaurs. For tens of millions of years, those great creatures had flourished. Then, suddenly, they disappeared. 如果冲击规模足够大，它可能会影响整个地球的环境并造成生态的大灾难。地质史上最完备记录下来的这种规模的冲击发生在65000W年前的白垩纪晚期。这次转折以大规模的灭绝为标记，约半数的物种全部灭绝。随然地质学记录上也有一些同等或更大规模的灭绝事件，但白垩纪大规模灭绝因为它标志着恐龙时代的完结而激起古生物学家的兴趣。千万年来，这种巨大的生物一直活跃着，然而却在那时突然消失了。catastrophe ktstrf cretaceous kriteis n. 大灾难; 大祸 adj. 白垩的, 白垩纪的n. 白垩纪, 白垩系intrigued intrigue intrigue | ntrgadj. 好奇的; 被迷住了的 n. 阴谋; 诡计v. 密谋; 私通; 激起.的兴趣paleontologist ,plintldistn. 古生物学者Paragraph 3: The body that impacted Earth at the end of the Cretaceous period was a meteorite with a mass of more than a trillion tons and a diameter of at least 10 kilometers. Scientists first identified this impact in 1980 from the worldwide layer of sediment deposited from the dust cloud that enveloped the planet after the impact. This sediment layer is enriched in the rare metal iridium and other elements that are relatively abundant in a meteorite but very rare in the crust of Earth. Even diluted by the terrestrial material excavated from the crater, this component of meteorites is easily identified. By 1990 geologists had located the impact site itself in the Yucat region of Mexico. The crater, now deeply buried in sediment, was originally about 200 kilometers in diameter. 白垩纪晚期撞击地球的是有着上亿吨重量和至少10公里直径的陨石。科学家在年首次通过撞击后世界范围内残留的尘雾沉积层确认了这次撞击活动。这层沉积物蕴含着丰富的稀有金属铱，而这种金属在地壳极为罕见，却在陨石中相对丰富。虽然被陨石坑中的地球物质所稀释，这种陨石中的成分仍可以轻松鉴别。年，地质学家认定撞击发生于墨西哥区。现在被深埋在沉淀层中的陨石坑，原本有约公里的直径。trillion triljn envelop envelop | nvelpn.大量,兆, 万亿 adj.兆的v. 包封; 包围; 遮盖dilute dailju:t terrestrial terrestrial | trestrlvt.稀释, 冲淡 adj.冲淡的, 稀释的adj. 地球的, 陆地的, 地上的component component | kmpnntn. 零件, 组成整件部分的单件; 构成要素; 成分Paragraph 4: This impact released an enormous amount of energy, excavating a crater about twice as large as the lunar crater Tycho. The explosion lifted about 100 trillion tons of dust into the atmosphere, as can be determined by measuring the thickness of the sediment layer formed when this dust settled to the surface. Such a quantity of material would have blocked the sunlight completely from reaching the surface, plunging Earth into a period of cold and darkness that lasted at least several months. The explosion is also calculated to have produced vast quantities of nitric acid and melted rock that sprayed out over much of Earth, starting widespread fires that must have consumed most terrestrial forests and grassland. Presumably, those environmental disasters could have been responsible for the mass extinction, including the death of the dinosaurs. 这次冲击释放出的巨大能量挖掘出一个有环形山两倍大的陨石坑。通过计算尘埃落地后形成沉积层的厚度，可以确定爆炸向大气层扬起了吨的灰尘。这样大量的灰尘足以将阳光完全阻隔，使地球笼罩于持续数月的阴冷黑暗中。同样有估计爆炸产生了大量硝酸，腐蚀了地表许多石头，引起了不断扩散的大火并将森林和草场毁灭。据推测，这一系列环境灾难与大规模灭绝，包括恐龙的死亡难逃干系。consume consume | knsjum presumably prizju:mbli v. 消耗; 消灭; 消费; 消灭; 毁灭adv.大概, 据推测, 可能Several other mass extinctions in the geological record have been tentatively identified with large impacts, but none is so dramatic as the Cretaceous event. But even without such specific documentation, it is clear that impacts of this size do occur and that their results can be catastrophic. What is a catastrophe for one group of living things, however, may create opportunities for another group. Following each mass extinction, there is a sudden evolutionary burst as new species develop to fill the ecological niches opened by the event. 地质记录上其他的几次大规模灭绝也被实验性地与大规模撞击相联系，但没有一次像白垩纪这样剧烈。虽然没有明确的记录，但很明显如此规模的撞击确实发生过并造成灾难性后果。然而对一种族群可能是大灾难的事件，有可能为另一种族群创造机会。每次大规模灭绝后，都会忽然有剧烈的进化活动产生新的物种来弥补事件造成的生态空缺。tentatively tenttivli adv. 试验性地, 犹豫不决地Paragraph 6: Impacts by meteorites represent one mechanism that could cause global catastrophes and seriously influence the evolution of life all over the planet. According to some estimates, the majority of all extinctions of species may be due to such impacts. Such a perspective fundamentally changes our view of biological evolution. The standard criterion for the survival of a species is its success in competing with other species and adapting to slowly changing environments. Yet an equally important criterion is the ability of a species to survive random global ecological catastrophes due to impacts. 陨石冲击可能造成全球性灾难和对整个星球生物进化的极大影响。据某些估计，大多数物种灭绝都与此类撞击有关。这种观点从根本上改变了生物进化观念。幸存下来的标准准则是物种成功在与其他物种的竞争中获胜和对变化中环境的适应。然而现在一个同等重要的准则是，物种能否在随机的撞击引起的全球性生态灾害中幸存。mechanism meknizm perspective pspektiv n.机制, 原理 n.远景, 看法, 透视 adj.透视的criterion kraitirin n.标准, 准则Paragraph 7: Earth is a target in a cosmic shooting gallery, subject to random violent events that were unsuspected a few decades ago. In 1991 the United States Congress asked NASA to investigate the hazard posed today by large impacts on Earth. The group conducting the study concluded from a detailed analysis that impacts from meteorites can indeed be hazardous. Although there is always some risk that a large impact could occur, careful study shows that this risk is quite small. 地球是宇宙靶场的一个目标，是这种数十年前还无法预测的随机暴力事件的对象。年美国国会要求研究现在撞击对地球的潜在危险。调查组通过一系列细致的分析总结出陨石确实是随机而危险的。虽然仍有大规模撞击发生的危险性，严谨的调查表明这样的风险是很小的。（81） It was not until after the Second World War that physicists began trying to make stimulated emission dominate. 直到第二次世界大战之后，物理学家开始尝试强化受激发射。stimulate stimulate | stmjlet /-jl-v. 刺激, 鼓舞, 激励; 有刺激之作用; 起促进作用emission imin n.散发, 发行, 排放dominate dmineit v. 支配, 占优势, 俯视（82） Wooden planks were joined, covered with gesso to prepare the surface for painting, and then polished smooth with special tools. 用覆盖着石膏的厚木板来准备图画，再用特殊的工具将其磨光plank plkn. 厚木板, 政纲条款, 支架v. 铺板, 立刻付款gesso desu n. 石膏, 石膏底polish polish | pl /pln. 光泽, 精良, 优雅v. 磨光, 擦亮; 润饰; 使优美, 使精炼; 发亮, 变光滑（83） It was, therefore, an ideal technique for emphasizing the hard linear edges and pure, fine areas of color that were so much a part of the overall aesthetic of the time. 因此，在强调当时属于总体美学的一部分的坚硬的线性边缘和纯洁美丽的颜色方面，它是一项理想的技术。这是一种理想的技术，它可以强调边缘的线条感，美化纯净化色彩使之能成为永恒的美emphasize emphasize | emfsazv. 强调, 着重, 加强语气（84） Being so educable, individual birds have markedly different interests and inclinations, strategies and scams. 各种可教育的鸟类有着完全相异的兴趣、意愿、策略和阴谋。因为非常能学东西，个体乌鸦间有非常不同的兴趣和爱好，战略和诡计。inclination inclination | nklnenn. 倾向, 倾斜度, 意愿scam skmn. 骗钱; 阴谋; 诈取; 骗局（85） These researchers have sought to demonstrate that their work can be a valuable tool not only of science but also of history, providing fresh insights into the daily lives of ordinary people whose existences might not otherwise be so well documented.这些研究人员试图证明他们的工作是一件对于科学和历史都是颇具价值的工具，并提供对普通人日常生活的深入了解，否则他们的存在不会被如此完好的记载下来。调查人员想要证明他们的工作不只是科学上更是能载入史册的有用的工具，用崭新的视野观察普通人的日常生活，而这些人的存在恰是没有被认真记录的。（86） On the other hand, when it comes to substantive-particularly behavioral-information, crows are less well known than many comparably common species and, for that matter, not a few quite uncommon ones: the endangered California condor, to cite one obvious example. 另一方面，说到特定的行为信息，乌鸦并不如其他相对普通的种类出名。甚至是一些非常不寻常的，比如将要灭绝的加州秃鹫。（87） Keen observers and quick learners, they are astute about the intentions of other creatures, including researchers, and adept at avoiding them. 它们不愧是敏锐的观察家和快速的学习者，对其他生物的意向非常敏锐，包括调查人员它们能够非常熟练的躲开。keen ki:n adj.敏锐的, 强烈的, 锋利的, 热衷的, 精明的 （88） And in Sacramento an excavation at the site of a fashionable nineteenth-century hotel revealed that garbage had been stashed in the buildings basement despite sanitation laws to the contrary. 在XX19世纪流行的旅馆遗址中发现了无视公共卫生法藏在地下室的垃圾revealed rivi:ld stash st sanitation ,sanitation | snten发现, 透露, 显露 v. 藏起来,