练习1

Eight percent of the Earth’s crust is aluminum, and there are hundreds of aluminum-bearing minerals and vast quantities of the rocks that contain them. The best aluminum ore is bauxite, defined as aggregates of aluminous minerals, more or less impure, in which aluminum is present as hydrated oxides. Bauxite is the richest of all those aluminous rocks that occur in large quantities, and it yields alumina, the intermediate product required for the production of aluminum. Alumina also occurs naturally as the mineral corundum, but corundum is not found in large deposits of high purity, and therefore it is an impractical source for making aluminum. Most of the many abundant nonbauxite aluminous minerals are silicates, and, like all silicate minerals, they are refractory, resistant to analysis, and extremely difficult to process. The aluminum silicates are therefore generally unsuitable alternatives to bauxite because considerably more energy is required to extract alumina from them. 百分之八的地壳是铝,还有数百名aluminum-bearing矿物质和大量的岩石包含它们。最好的铝矿石铝土矿,定义为聚合铝的矿物,或多或少的不洁,铝和水合氧化物存在。铝土矿是最富有的那些发生在大量的铝岩石,而且收益率氧化铝,铝的生产所需的中间产品。氧化铝也自然发生的矿物刚玉,但没有找到刚玉在高纯度的大额存款,因此这是一个不切实际的铝源。大部分的许多丰富nonbauxite铝硅酸盐矿物,而且,像所有的硅酸盐矿物,耐火,耐分析,极难的过程。铝硅酸盐因此通常铝土矿不合适的替代品,因为它需要相当多的能量提取氧化铝。 6. The author implies that a mineral must either be or    readily supply which of the following in order to be    classified as an aluminum ore?   (A) An aggregate        (B) Bauxite  (C) Alumina        (D) Corundum (E) An aluminum silicate(C) 6。作者暗示一种矿物必须是或容易供应下列哪为了分为铝矿石吗?(一)一个聚合(B)铝土矿(C)氧化铝(D)刚玉(E)硅酸铝(C) 7. The passage supplies information for answering all of the following questions regarding aluminous minerals EXCEPT:   (A) What percentage of the aluminum in the Earth’s crust is in the form of bauxite?   (B) Are aluminum-bearing nonbauxite minerals plentiful?   (C) Do the aluminous minerals found in bauxite contain hydrated oxides? (D) Are aluminous hydrated oxides found in rocks?   (E) Do large quantities of bauxite exist?(A) 7。通过提供信息来回答所有关于铝矿石除了以下问 题 快递公司问题件快递公司问题件货款处理关于圆的周长面积重点题型关于解方程组的题及答案关于南海问题 :(A)的百分比铝在地壳中铝土矿的形式吗?(B)是aluminum-bearing nonbauxite矿物质充足吗?(C)铝土矿中的铝矿石包含水合氧化物?(D)铝水合氧化物中发现的岩石吗?(E)大量的铝土矿存在吗?(A) 8. The author implies that corundum would be used to  produce aluminum if (A)    corundum could be found that is not contaminated by silicates (B)    the production of alumina could be eliminated as an intermediate step in manufacturing aluminum (C) many large deposits of very high quality corundum were to be discovered (D) new technologies were to make it possible to convert corundum to a silicate (E) manufacturers were to realize that the world’s supply of bauxite is not unlimited(C) 8。作者暗示刚玉将用于生产铝如果(一)刚玉可能发现不受污染的硅酸盐(B)的生产氧化铝可以消除生产铝的中间步骤(C)许多大型存款非常高质量的刚玉被发现(D)新技术让我们可以把刚玉硅酸盐(E)制造商意识到,世界上的铝土矿供应不是无限的(C) Geologists have long known that the Earth’s mantle is heterogeneous, but its spatial arrangement remains unresolved—is the mantle essentially layered or irregularly heterogeneous? The best evidence for the layered mantle thesis is the well-established fact that volcanic rocks found on oceanic islands, islands believed to result from mantle plumes arising from the lower mantle, are composed of material fundamentally different from that of the mid-ocean ridge system, whose source, most geologists contend, is the upper mantle. Some geologists, however, on the basis of observations concerning mantle xenoliths, argue that the mantle is not layered, but that heterogeneity is created by fluids rich in “incompatible elements” (elements tending toward liquid rather than solid state) percolating upward and transforming portions of the upper mantle irregularly, according to the vagaries of the fluids’ pathways. We believe, perhaps unimaginatively, that this debate can be resolved through further study, and that the underexplored mid-ocean ridge system is the key. 9. Which of the following best expresses the main idea of the passage?   (A) Current theories regarding the structure of the Earth’s mantle cannot account for new discoveries regarding the composition of mantle xenoliths.   (B) There are conflicting hypotheses about the heterogeneity of the Earth’s mantle because few mantle elements have been thoroughly studied.   (C) Further research is needed to resolve the debate among geologists over the composition of the midocean ridge system.   (D) There is clear-cut disagreement within the geological community over the structure of the Earth’s mantle.   (E) There has recently been a strong and exciting challenge to geologists’ long-standing belief in the heterogeneity of the Earth’s mantle. 9。下列哪个最能表达段落的主要思想?(A)目前的理论关于地幔结构不能占新发现关于地幔捕虏的成分。(B)有相互矛盾的假设关于地球的地幔的异质性,因为很少有地幔元素彻底研究。(C)还需要进一步的研究来解决争论地质学家组成的洋中脊系统。(D)有明确的分歧在地质社区在地幔的结构。(E)最近有一个强大的和令人兴奋的挑战,地质学家长期以来对地幔的异质性。    10. According to the passage, it is believed that oceanic islands are formed from   (A) the same material as mantle xenoliths   (B) the same material as the midocean ridge system   (C) volcanic rocks from the upper mantle   (D) incompatible elements percolating up from the lower mantle   (E) mantle plumes arising from the lower mantle . It can be inferred from the passage that the supporters of the “layered-mantle” theory believe which of the following? I. The volcanic rocks on oceanic islands are composed of material derived from the lower part of the mantle. II. The materials of which volcanic rocks on oceanic islands and midocean ridges are composed are typical of the layers from which they are thought to originate. III. The differences in composition between volcanic rocks on oceanic islands and the midocean ridges are a result of different concentrations of incompatible elements.   (A) I only    (B) III only    (C) I and II only  (D) II and III only    (E) I, II, and III 地质学家早就知道地球的地幔是异类,但从本质上说,其空间布置仍然unresolved-is地幔层状或不规则异构?分层地幔的最佳证据的论文是既定的事实,火山岩上发现海洋岛屿,岛屿被认为来自下地幔的地幔柱状溶岩流——上,是由与海洋中部山脊系统的物质根本不同的洋中脊系统,其来源,大多数地质学家认为,是上地幔。然而,某些地质学家,以对地幔捕虏岩体所作的观察为依据,指出地幔并非是分层排列的,相反,地幔的异质性是由液体丰富的“不相容元素”的,这些成分趋向于流体而非固体的状态,自下而上渗透扩散,不规则地将上部地幔的某些部分予以改变,根据这些流质的途径。也许没有想象力,我们相信,这场辩论可以通过进一步的研究,来解决,前后洋中脊系统是关键。 12. The authors suggest that their proposal for determining the nature of the mantle’s heterogeneity might be considered by many to be   (A) pedestrian    (B) controversial  (C) unrealistic    (D) novel (E) paradoxical Diamonds, an occasional component of rare igneous rocks called lamproites and kimberlites, have never been dated satisfactorily. However, some diamonds contain minute inclusions of silicate minerals, commonly olivine, pyroxene, and garnet. These minerals can be dated by radioactive decay techniques because of the very small quantities of radioactive trace elements they, in turn, contain. Usually, it is possible to conclude that the inclusions are older than their diamond hosts, but with little indication of the time interval involved. Sometimes, however, the crystal form of the silicate inclusions is observed to resemble more closely the internal structure of diamond than that of other silicate minerals. It is not known how rare this resemblance is, or whether it is most often seen in inclusions of silicates such as garnet, whose crystallography is generally somewhat similar to that of diamond; but when present, the resemblance is regarded as compelling evidence that the diamonds and inclusions are truly cogenetic 钻石,偶尔的组件称为lamproites的罕见的火成岩和kimberlites,从未过时。然而,一些钻石包含分钟夹杂物的硅酸盐矿物,通常橄榄石、辉石、石榴石。这些矿物质可以由放射性衰变过时的技术,因为非常少量的放射性微量元素,包含。通常,可以得出这样的结论:夹杂物比钻石主机,但几乎没有迹象表明涉及的时间间隔。有时,然而,晶体形式的硅酸盐夹杂物更紧密地观察到像钻石的内部结构比其他硅酸盐矿物。不知这种类似稀少到何种地步,也不知道是否它最常见于象石榴石一类的硅酸盐内含物中,而这类物质的晶体结构普遍地某种程度上类似于金刚石的晶体结构。但当礼物,相似之处被视为令人信服的证据表明,钻石和夹杂物尚不知 13. The author implies that silicate inclusions were most often formed (A) with small diamonds inside of them  (B) with trace elements derived from their host minerals  (C) by the radioactive decay of rare igneous rocks  (D) at an earlier period than were their host minerals (E) from the crystallization of rare igneous material 14. According to the passage, the age of silicate minerals included in diamonds can be determined due to a feature of the   (A) trace elements in the diamond hosts   (B) trace elements in the rock surrounding the diamonds   (C) trace elements in the silicate minerals   (D) silicate minerals’ crystal structure   (E) host diamonds’ crystal structure 15. The author states that which of the following generally has a crystal structure similar to that of diamond?   (A) Lamproite        (B) Kimberlite  (C) Olivine      (D) Pyroxene      (E) Garnet 16. The main purpose of the passage is to (A) explain why it has not been possible to determine the age of diamonds   (B) explain how it might be possible to date some diamonds   (C) compare two alternative approaches to determining the age of diamonds   (D) compare a method of dating diamonds with a method used to date certain silicate minerals   (E) compare the age of diamonds with that of certain silicate minerals contained within them Volcanic rock that forms as fluid lava chills rapidly is called pillow lava. This rapid chilling occurs when lava erupts directly into water (or beneath ice) or when it flows across a shoreline and into a body of water. While the term “pillow lava” suggests a definite shape, in fact geologists disagree. Some geologists argue that pillow lava is characterized by discrete, ellipsoidal masses. Others describe pillow lava as a tangled mass of cylindrical, interconnected flow lobes. Much of this controversy probably results from unwarranted extrapolations of the original configuration of pillow flows from two-dimensional cross sections of eroded pillows in land outcroppings. Virtually any cross section cut through a tangled mass of interconnected flow lobes would give the appearance of a pile of discrete ellipsoidal masses. Adequate three-dimensional images of intact pillows are essential for defining the true geometry of pillowed flows and thus ascertaining their mode of origin. Indeed, the term “pillow,” itself suggestive of discrete masses, is probably a misnomer. 火山岩形成液体熔岩发冷迅速叫枕状熔岩。这种快速冷却时发生火山岩浆直接在水(或冰下)或当它流在海岸线和水体。而“枕状熔岩”一词表明一个明确的形状,事实上地质学家不同意。一些地质学家认为,枕状熔岩特点是离散的,椭圆形。别人描述枕状熔岩团的圆柱形、相互关联的流叶。这种争议可能毫无根据的推断结果的原始配置的侵蚀枕头枕流二维横截面土地露出。任何截面穿过一团相互连接的流叶会给一堆离散椭圆的外观质量。足够的三维图像完整的枕头是必不可少的定义一张流动的真实几何形状,从而确定起源的模式。事实上,这个词“枕头”,本身暗示离散的群众,可能是用词不当。 17. Which of the following is a fact presented in the passage?   (A) The shape of the connections between the separate, sacklike masses in pillow lava is unknown.   (B) More accurate cross sections of pillow lava would reveal the mode of origin.   (C) Water or ice is necessary for the formation of pillow lava.   (D) No three-dimensional examples of intact pillows currently exist.   (E) The origin of pillow lava is not yet known. 18. In the passage, the author is primarily interested in   (A) analyzing the source of a scientific controversy   (B) criticizing some geologists’ methodology   (C) pointing out the flaws in a geological study   (D) proposing a new theory to explain existing scientific evidence   (E) describing a physical phenomenon 19. The author of the passage would most probably agree that the geologists mentioned in line 4 (“Some geologists”) have made which of the following errors in reasoning?       I. Generalized unjustifiably from available evidence.     II. Deliberately ignored existing counterevidence.   III. Repeatedly failed to take new evidence into account.   (A) I only    (B) II only    (C) III only (D) I and II only    (E) II and III only 20. The author implies that the “controversy” (line 7) might be resolved if   (A) geologists did not persist in using the term “pillow”   (B) geologists did not rely on potentially misleading information   (C) geologists were more willing to confer directly with one another   (D) two-dimensional cross sections of eroded pillows were available   (E) existing pillows in land outcroppings were not so badly eroded   The term “Ice Age” may give a wrong impression. The epoch that geologists know as the Pleistocene and that spanned the 1.5 to 2.0 million years prior to the current geologic epoch was not one long continuous glaciation, but a period of oscillating climate with ice advances punctuated by times of interglacial climate not very different from the climate experienced now. Ice sheets that derived from an ice cap centered on northern    Scandinavia reached southward to Central Europe. And beyond the margins of the ice sheets, climatic oscillations affected most of the rest of the world; for example, in the deserts, periods of wetter conditions (pluvials) contrasted with drier, interpluvial periods. Although the time involved is so short, about 0.04 percent of the total age of the Earth, the amount of attention devoted to the Pleistocene has been incredibly large, probably because of its immediacy, and because the epoch largely coincides with the appearance on Earth of humans and their immediate ancestors. There is no reliable way of dating much of the Ice Age. Geological dates are usually obtained by using the rates of decay of various radioactive elements found in minerals. Some of these rates are suitable for very old rocks but involve increasing errors when used for young rocks; others are suitable for very young rocks and errors increase rapidly in older rocks. Most of the Ice Age spans a period of time for which no element has an appropriate decay rate.   Nevertheless, researchers of the Pleistocene epoch have developed all sorts of more or less fanciful model schemes of how they would have arranged the Ice Age had they been in charge of events. For example, an early classification of Alpine glaciation suggested the existence there of four glaciations, named the Gunz, Mindel, Riss, and Wurm. This succession was based primarily on a series of deposits and events not directly related to glacial and interglacial periods, rather than on the more usual modern method of studying biological remains    found in interglacial beds themselves interstratified within glacial deposits. Yet this succession was forced willy-nilly onto the glaciated parts of Northern Europe, where there are partial successions of true glacial ground moraines and interglacial deposits, with hopes of ultimately piecing them together to provide a complete Pleistocene succession. Eradication of the Alpine nomenclature is still proving a Herculean task. There is no conclusive evidence about the relative length, complexity, and temperatures of the various glacial and interglacial periods. We do not know whether we live in a postglacial period or an interglacial period. The chill truth seems to be that we are already past the optimum climate of postglacial time. Studies of certain fossil distributions and of the pollen of certain temperate plants suggest decreases of a degree or two in both summer and winter temperatures and, therefore, that we may be in the declining climatic phase leading to glaciation and extinction. 6. In the passage, the author is primarily concerned with   (A) searching for an accurate method of dating the Pleistocene epoch   (B) discussing problems involved in providing an accurate picture of the Pleistocene epoch   (C) declaring opposition to the use of the term “Ice Age” for the Pleistocene epoch   (D) criticizing fanciful schemes about what  happened in the Pleistocene epoch   (E) refuting the idea that there is no way to tell if we are now living in an Ice Age 7. The “wrong impression” (line 1) to which the author refers is the idea that the   (A) climate of the Pleistocene epoch was not very different from the climate we are now experiencing   (B) climate of the Pleistocene epoch was composed of periods of violent storms   (C) Pleistocene epoch consisted of very wet, cold periods mixed with very day, hot periods   (D) Pleistocene epoch comprised one period of continuous glaciation during which Northern Europe was covered with ice sheets   (E) Pleistocene epoch had no long periods during which much of the Earth was covered by ice 8. According to the passage, one of the reasons for the deficiencies of the “early classification of Alpine glaciation” (lines 29-30) is that it was   (A) derived from evidence that was only tangentially related to times of actual glaciation   (B) based primarily on fossil remains rather than on actual living organisms   (C) an abstract, imaginative scheme of how the period might have been structured (D) based on unmethodical examinations of randomly chosen glacial biological remains (E) derived from evidence that had been haphazardly gathered from glacial deposits and inaccurately evaluated 9. Which of the following does the passage imply about the “early classification of Alpine glaciation” (lines 29-30)?   (A) It should not have been applied as widely as it was.   (B) It represents the best possible scientific practice,    given the tools available at the time. (C) It was a valuable tool, in its time, for measuring        the length of the four periods of glaciation.   (D) It could be useful, but only as a general guide to the events of the Pleistocene epoch.   (E) It does not shed any light on the methods used at the time for investigating periods of glaciation. 10. It can be inferred from the passage that an important result of producing an accurate chronology of events of the Pleistocene epoch would be a   (A) clearer idea of the origin of the Earth   (B) clearer picture of the Earth during the time that      humans developed   (C) clearer understanding of the reasons for the    existence of deserts   (D) more detailed understanding of how radio active dating of minerals works   (E) firmer understanding of how the northern polar        ice cap developed 11. The author refers to deserts primarily in order to   (A) illustrate the idea that an interglacial climate is      marked by oscillations of wet and dry periods   (B) illustrate the idea that what happened in the deserts during the Ice Age had far-reaching effects even on the ice sheets of Central and Northern Europe (C) illustrate the idea that the effects of the Ice Age’s climatic variations extended beyond the areas of ice (D) support the view that during the Ice Age sheets of ice covered some of the deserts of the world   (E) support the view that we are probably living in a postglacial period 12. The author would regard the idea that we are living in an interglacial period as   (A) unimportant   (B) unscientific   (C) self-evident   (D) plausible   (E) absurd