托福TPO解析TPO20 Fossil Preservation

Q1 The word “agencies” in the passage is closest in meaning to ○Combinations ○Problems ○Forces ○Changes Q2 In paragraph 1, what is the author’s purpose in providing examples of how organisms are destroyed? ○To emphasize how surprising it is that so many fossils exist ○To introduce a new geologic theory of fossil preservation ○To explain why the fossil record until now has remained incomplete ○To compare how fossils form on land and in water Q3 The word “terrestrial” in the passage is closest in meaning to ○Land ○Protected ○Alternative ○Similar Q4 Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change in the meaning in important ways or leave out essential information. A When snail or clam shells are left behind, they must be empty in order to remain durable and resist dissolution. B Although snail and clam shells are durable and resist dissolving, over time they slowly begin to change. C Although the soft parts of snails or clams dissolve quickly, their hard shells resist dissolution for a long time. D Empty snail or clam shells that are strong enough not to dissolve may stay in their original state for a long time. Q5 Why does the author mention “aragonite” in the passage? ○To emphasize that some fossils remain unaltered for millions of years. ○To contrast fossil formation in organisms with soft tissue and in organisms with hard shells ○To explain that some marine organisms must undergo chemical changes in order to fossilize ○To explain why fossil shells are more likely to survive than are fossil skeletons. Q6 The word “enhance” in the passage is closest in meaning to ○Control ○Limit ○Combine ○Increase Q7 Which of the following best explains the process of permineralization mentioned in paragraph 3? ○Water containing calcium carbonate circulates through a shell and deposits sediment. ○Liquid containing chemicals hardens an already existing fossil structure. ○Water passes through sediment surrounding a fossil and removes its chemical content. ○A chemical substance enters a fossil and changes its shape. Q8 The word “precise” in the passage is closest in meaning to ○Complex ○Quick ○Exact ○Reliable http://www.ibtsat.com Q9 Paragraph 5 suggests which of the following about the carbonization process? ○It is completed soon after an organism dies. ○It does not occur in hard-shell organisms. ○It sometimes allows soft-tissued organisms to be preserved with all their parts. ○It is a more precise process of preservation than is replacement. Q10 The word “prospect” in the passage is closest in meaning to ○Completion ○Variety ○Possibility ○Speed Q11 According to paragraph 7, how do environments containing oxygen affect fossil preservation? ○They increase the probability that soft-tissued organisms will become fossils. ○They lead to more bacteria production. ○They slow the rate at which clay and silt are deposited. ○They reduce the chance that animal remains will be preserved. Q12 According to the passage, all of the following assist preservation EXCEPT ○The presence of calcite in an organism’s skeleton ○The presence of large open areas along an ocean floor ○The deposition of a fossil n sticky substances such as sap or tar ○The rapid burial of an organism under layers of silt Q13 Look at the four squares that indicate where the following sentence can be added to the passage. But the evidence of past organic life is not limited to petrifaction. Where would the sentence best fit? Click on a square■ to insert the sentence in the passage. Q14 The remains of ancient life are amazingly well preserved in the form of fossils. Answer choices A Environmental characteristics like those present on ocean floors increase the likelihood that plant and animal fossils will occur. B Fossils are more likely to the preserved in shale deposits than in deposits of clay and silt. C The shells of organisms can be preserved by processes of chemical precipitation or mineral exchange. D Freezing enables the soft parts of organisms to survive longer than the hard parts. E Comparatively few fossils are found in the terrestrial deposits of streams and lakes. F Thin films of carbon may remain as an indication of soft tissue or actual tissue may be preserved if exposure to bacteria is limited. Fossil preservation When one considers the many ways by which organisms are completely destroyed after death, it is remarkable that fossils are as common as they are. Attack by scavengers and bacteria, chemical decay, and destruction by erosion and other geologic agencies make the odds against preservation very high. However, the chances of escaping complete destruction are vastly improved if the organism happens to have a mineralized skeleton and dies in a place where it can be quickly buried by sediment. Both of these conditions are often found on the ocean floors, where shelled invertebrates (organisms without spines) flourish and are covered by the continuous rain of sedimentary particles. Although most fossils are found in marine sedimentary rocks, they also are found in terrestrial deposits left by streams and lakes. On occasion, animals and plants have been preserved after becoming immersed in tar or quicksand, trapped in ice or lave flows, or engulfed by rapid falls of volcanic ash. The term “fossil” often implies petrifaction, literally a transformation into stone. After the death of an organism, the soft tissue is ordinarily consumed by scavengers and bacteria. They empty shell of a snail or clam may be left behind, and if it is sufficiently durable and resistant to dissolution, it may remain basically unchanged for a long period of time. Indeed, unaltered shells of marine invertebrates are known from deposits over 100 million years old. In many marine creatures, however, the skeleton is composed of mineral variety of calcium carbonate called aragonite. Although aragonite has the same composition as the more familiar mineral known as calcite, it has a different crystal form, is relatively unstable, and in time changes to the more stable calcite. =>Many other processes may after the shell of the clam or snail and enhance its chances for preservation. Water containing dissolved silica, calcium carbonate, or iron many circulate through the enclosing sediment and be deposited in cavities such as narrow cavities and canals in bone once occupied by blood vessels and nerves. In such cases, the original composition of the bone or shell remains, but the fossil is made harder and more durable. This addition of a chemically precipitated substance into precipitated is termed “permineralization.” Petrifaction may also involve a simultaneous exchange of the original substance of a dead plant or animal with mineral matter of a different composition. This process is termed “replacement” because solutions have dissolved the original material and replaced it with an equal volume of the new substance. Replacement can be a marvelously precise process, so that details of shell ornamentation, tree rings in wood, and delicate structures in bone are accurately preserved. =>■Another type of fossilization, known as carbonization, occurs when soft tissues are preserved as thin film of carbon.■ Leaves and tissue of soft-bodied organisms such as jellyfish or worms may accumulate, become buried and compressed, and lose their volatile constituents.■ The carbon often remains behind as a blackened silhouette.■ Although it is certainly true that the possession of hard parts enhances the prospect of preservation, organisms having soft tissues and organs are also occasionally preserved. Insects and even small invertebrates have been found preserved in the hardened resins of conifers and certain other trees. X-ray examination of thin slabs of roc sometimes reveals the ghostly outlines of tentacles, digestive tracts, and visual organs of a variety of marine creatures. Soft parts, including skin, hair, and viscera of ice age mammoths, have been preserved in frozen soil or in the oozing tar of oil seeps. =>The probability that actual remains of soft tissue will be preserved is improved if the organism dies in an environment of rapid deposition and oxygen deprivation. Under such conditions, the destructive effects of bacteria are diminished. The middle Eocene Messel shale (from about 48 million years ago) of German accumulated in such an environment. The shale was deposited in an oxygen-deficient lake where lethal gases sometimes bubbled up and killed animals. Their remains accumulated on the floor of the lake and were then covered by clay and silt. Among the superbly preserved Messel fossils are insects with iridescent exoskeletons (hard outer coverings), frogs with skin and blood vessels intact, and even entire small mammals with preserved fur and soft tissue. TPO20 Fossil Preservation 1. 与单词agencies在文中意思最接近的是 （Vocabulary Question） a) Combinations （结合） b) Problems （问题） c) Forces （力量） d) Changes （改变） 解析：agency n.代理。没有直接的同义词，于是回到原句“Attack by scavengers and bacteria, chemical decay, and destruction by erosion and other geologic agencies make the odds against preservation very high.”意思是：师傅动物和细菌的攻击，化学腐烂，侵蚀的破坏以及其他地理力量使得保存几率不大。这里的geologic agencies可以直译为地理代理，但是与前面排列的元素，比如破坏，化学腐烂和侵蚀，这些都可以被看做是阻碍保存的力量载体。 2. 作者举出生物如何被毁坏的例子的目的是什么？ （Rhetorical Purpose Question） a) 强调这么多化石的存在多么令人感到惊讶。 b) 引入一个新的化石保存的地质理论。 c) 解释为什么化石记录直到现在都保持不完整。 d) 比较化石如何在陆地上形成以及如何在水中形成。 解析：首先会段落找到这些例子，这些例子就在第二句话中。往前看第一句“When one considers the many ways by which organisms are completely destroyed after death, it is remarkable that fossils are as common as they are.”意思是：当考虑到生物死亡后被完全毁灭的多种方式时，一定觉得惊讶化石还是非常普遍的。第二句举得例子就是详细阐述了生物死亡后多种多样被毁灭的方式。 3. 与单词terrestrial在文中意思最接近的是 （Vocabulary Question） a) Land （陆地） b) Protected （被保护的） c) Alternative （另外的选择） d) Similar （类似的） 解析：terrestrial a.陆地的，陆生的。 4. 以下哪一项能表达出高亮句子的精华核心含义？错误选项改变重要含义或者遗漏精华信息。 The empty shell of a snail or clam may be left behind, and if it is sufficiently durable and resistant to dissolution, it may remain basically unchanged for a long period of time. 蜗牛和蛤的空壳留了下来，且若足够持久耐不溶解，就可能长时间保持基本不变。 a) 当蜗牛和蛤被留下来，它们必须是空的，这样才能持久并且抵抗溶解。 b) 尽管蜗牛和蛤的壳耐久且抗溶解，久而久之它们还是会慢慢改变。 c) 尽管蜗牛或者蛤的软体部分溶解很快，它们硬件部分能够长时间抵抗溶解。 d) 空的蜗牛和蛤的壳，若强到足够抵抗溶解，则可能长时间保持原状态。 5. 为什么作者要在文中提到“aragonite”？ （Rhetorical Purpose Question） a) 强调一些话是要保持上百万年不变 b) 比较有软体组织的生物化石形成和有硬壳的生物化石形成 c) 解释一些海洋生物要经过化学变化才能变成化石 d) 解释为什么化石壳比化石骨架更可能留存 解析：找原句，往前看，发现并不能提供任何有效线索，于是往后看，段落最后一句“Although aragonite has the same composition as the more familiar mineral known as calcite, it has a different crystal form, is relatively unstable, and in time changes to the more stable calcite.”意思是：尽管aragonite与熟知的方解石有相同的组成，但她相对不稳定会随着时间变成更稳定的方解石。只有选项三符合。 选项一错，段落强调过时间。 选项二错，没对软体组织生物和硬体组织生物做过比较。 选项四错，同样，段落没做过次比较。 6. 与单词enhance在文中意思最接近的是 （Vocabulary Question） a) Control （控制） b) Limit （限制） c) Combine （合并） d) Increase （增加） 解析：查字典：To enhance is to increase or further improve the good quality, value or status of sb/sth；释义来自牛津高阶。 7. 以下哪项能最好地解释第三段中题到的permineralization过程？ （Factual Information Question） a) 包含碳酸钙的水在壳与沉淀物中循环。 b) 包含化学物质的液体加硬已经存在的化石结构。 c) 水穿过围着化石的沉淀物并且移除化石内含的化学物质。 d) 化学物质进入化石并且改变化石的形状。 解析：段落第二句和第三句“Water containing dissolved silica, ……blood vessels and nerves. In such cases, ……is made harder and more durable.”意思是：溶解了硅和碳酸钙或铁的水在封闭的沉淀物种循环，并在原来被血管和神经占据的骨髓穴和骨头管道中沉淀。这种情况下，骨头或者壳的组成保持不变，但化石变得更硬更耐久。 选项一错，没有谈到变的更硬更耐久的结果。 选项三错，这一过程是不会溢出化石中内含的化学物质的。 选项四错，不会改变化石的形状。 8. 与单词precise在文中意思最接近的是 （Vocabulary Question） a) Complex （复杂的） b) Quick （快速的） c) Exact （精确的） d) Reliable （可靠的） 解析：precise adjective. Exact and accurate; 释义来自剑桥高级学习词典。 9. 第五段暗示了以下哪项关于碳化的过程？ （Inference Question） a) 生物死后，这个过程就迅速完成。 b) 这个过程不会在硬壳生物中出现。 c) 这一过程可能保存软体生物的所有部分。 d) 这个过程相比替代过程更精确。 解析：第一句是这一过程的定义“Another type of fossilization, known as carbonization, occurs when soft tissues are preserved as thin films of carbon.”意思是：另外一种石化的类型是碳化，发生时软体组织以薄碳片的形式被保存下来。定义里面就只包括软体组织，没有硬壳，所以这一过程肯定不会发生在硬壳生物中，若真的发生了，根据定义，那也就不能称之为碳化了。 10. 与单词prospect在文中意思最接近的是 （Vocabulary Question） a) Completion （完成） b) Variety （多种多样） c) Possibility （可能性） d) Speed （速度） 解析：查字典：Prospect ： the possibility that something good might happen in the future；释义来自剑桥高级学习词典。 11. 根据第七段，有氧环境如何影响化石保存？ （Factual Information Question） a) 它们增加了软体动物变成化石的几率。 b) 它们导致更多细菌的产生。 c) 它们降低了粘土和淤泥的沉淀速度。 d) 它们减少了动物残骸被保存的几率。 解析：第一句“The probability that actual remains of soft tissue will be preserved is improved if the organism dies in an environment of rapid deposition and oxygen deprivation.”意思是：软体残骸被保存的几率会有所提升，如果生物体是在迅速沉淀且无氧的环境。那么言下之意，就是若有氧气，残骸保存的几率肯定就会下降了。 12. 根据文章，哪项不会促进化石保存？ （Negative Factual Information Question） a) 生物骨架中方解石的出现 b) 海底出现大开口 c) 化石在粘性物质如树液或柏油中沉淀 d) 在淤泥层下生物迅速被掩埋 解析：选项一对，第二段最后一句说了方解石更稳定，当然促进化石保存了。 选项三对，第六段中提到在树脂中柏油中形成化石的例子，想想琥珀就知道了。 选项四对，第七段开头就提到了。 选项二错，虽然第一段有提到ocean floor，但是有个大开口好像并不会促进化石的保存。 13. But the evidence of past organic life is not limited to petrifaction. 但是过去有机生命的证据不仅仅限于石化. 解析：解题的关键在于petrifaction，整个段落都在谈carbonization，所以只能插入第一个插入口，承接上一段对petrifaction的描述。因此 答案 八年级地理上册填图题岩土工程勘察试题省略号的作用及举例应急救援安全知识车间5s试题及答案 是第一个插入口。 14. The remains of ancient life are amazingly well preserved in the form of fossils. 古老生命的残骸非常令人惊讶的以化石的形式保存下来了。 a) 环境特点，比如：海底那样的环境，是能够增加动植物化石出现的几率的。 b) 化石更有可能在页岩沉淀物中而不是粘土和淤泥中保存。 c) 生命体的壳可以通过化学沉淀或者矿物质交还的过程保存。 d) 冰冻能够使生命体中软体部分保存的时间比硬体部分长。 e) 在溪水和湖水中的岩石沉淀物中发现的化石相对较少。 f) 在对细菌的暴露不多的情况下，碳薄膜可能是软体组织或组织被保存的象征。 解析：选项一对，第一段中的主要内容； 选项二错，没有做过页岩沉淀物和粘土以及淤泥的比较； 选项三对，第三段中说的permineralization其实就是一种化学沉淀，第四段讲的replacement就是物质交换； 选项四错，没谈到冰冻的效果； 选项五错，无此比较； 选项六对，第五段有碳化过程中碳薄膜的叙述，而全文不止一处提到细菌对软体组织的腐蚀作用，所以当然在细菌有限的情况下，碳薄膜可以作为软体组织化石保存的象征了。 因此，答案是：1,3,6；