托福机经：2014年9月27托福阅读真题解析

 

　　第一套题

　　第一篇：

　　大陆漂移

　　关于大陆漂移、分离说。说最开始有人认为所有大陆很久以前是一块，后来有人提出不同观点，因为大洋两岸的大陆的coastline没办法很好地结合起来，这是人们发现海底的一个什么可以合起来，这是一个支持的evidence，并且认识到coastline合不起来是因为上面有erosion(此处有题)

　　第二段说最开始的一块分成了南北两块，下面论述为什么能证明南北两块原来是一块。从气候和化石还有冰川作用来证明的(这里逻辑和细节记不清了，大意就是现在不该有冰川的地方还有冰川痕迹，现在不在热带的地方有一些热带动物植物化石)后面还说了山脉也可以证明，这里说了洛基山脉、喜马拉雅山。还说爱尔兰啊什么的，他们的山脉可以拼到一起去。这证明他们原来是一块。

　　解析：本文讲解经典话题大陆漂移，也是从经典加试开始就经常出现的话题，本篇在写的时候侧重大陆漂移理论的形成过程，在理解过程中考生应该重点关注每个阶段不同的证据支撑的理论侧重方面。

　　参考阅读：

　　Continental Drift

　　Continental drift is the movement of the Earth's continents relative to each other by appearing to drift across the ocean bed. The speculation that continents might have 'drifted' was first put forward by Abraham Ortelius in 1596. The concept was independently and more fully developed by Alfred Wegener in 1912, but his theory was rejected for being incomplete. The idea of continental drift has been subsumed by the theory of plate tectonics, which explains how the continents move.

　　Evidence of continental 'drift'

　　Evidence for the movement of continents on tectonic plates is now extensive. Similar plant and animal fossils are found around different continent shores, suggesting that they were once joined. The fossils of Mesosaurus, a freshwater reptile rather like a small crocodile, found both in Brazil and South Africa, are one example; another is the discovery of fossils of the land reptile Lystrosaurus from rocks of the same age from locations in South America, Africa, and Antarctica. There is also living evidence—the same animals being found on two continents. Some earthworm families (e.g.: Ocnerodrilidae, Acanthodrilidae, Octochaetidae) are found in South America and Africa, for instance.

　　The complementary arrangement of the facing sides of South America and Africa is obvious, but is a temporary coincidence. In millions of years, slab pull and ridge-push, and other forces of tectonophysics will further separate and rotate those two continents. It was this temporary feature which inspired Wegener to study what he defined as continental drift, although he did not live to see his hypothesis become generally accepted.

　　Widespread distribution of Permo-Carboniferous glacial sediments in South America, Africa, Madagascar, Arabia, India, Antarctica and Australia was one of the major pieces of evidence for the theory of continental drift. The continuity of glaciers, inferred from oriented glacial striations and deposits called tillites, suggested the existence of the supercontinent of Gondwana, which became a central element of the concept of continental drift. Striations indicated glacial flow away from the equator and toward the poles, in modern coordinates, and supported the idea that the southern continents had previously been in dramatically different locations, as well as contiguous with each other.#p#副标题#e#

　　第二篇：

　　版本一：

　　爬行动物蛋和厚度变化，不难，一段一种假说。

　　貌似第一种是从水生转变为陆地过程，很模糊，因为谷歌已经一样了，在岸上产蛋可以远离水里面的不是这，但还要防止岸上的捕食者。

　　中间有几种，有一种说蛋变大了，数量就比以前少了，但是也够了，便大部分就有空间存储iron，因为iron有毒，以前的大小不可以，这里考了单词题accumulating。

　　最后一种是G不透气，不好送O2，然后就有一种新的透气的。

　　版本二：

　　讲蛋壳的形成。开头没太懂，好像是说蛋壳的形成和很久以前reptile变amphibian的过程有关?说reptile变amphibian没有一个明确的时间，没有明确分界(此处有题)

　　后面介绍了三种explanation。第一种认为，水中环境危险所以要产在陆地上，however陆地也有risks，为了保护要分泌的一种毒素，毒素积攒就变成了硬壳。第二种说当时气候变冷，所以下的蛋变大，数量变少。第三种说了蛋壳不会太大，因为外面有一层物质，这种物质不擅长吸收水分，过大的蛋的不到足够水。不过后来的一种物质的出现改善了这个问题，这种新物质吸水性好一些。

　　解析：本文讲解蛋壳形成的过程，应该是重复20130302NA题。通过几个假设解释了该过程，具体结构可以参考TPO中The Mystery of Yawning这篇文章，在理解过程中重点抓住三种解释的观点以及合理性问题。

　　参考阅读：

　　An eggshell is the outer covering of a hard-shelled egg and of some forms of eggs with soft outer coats. Bird eggshells contain calcium carbonate and dissolve in various acids, including the vinegar used in cooking. While dissolving, the calcium carbonate in an egg shell reacts with the acid to form carbon dioxide.

　　Insect eggs

　　Insects and other arthropods lay a variety of styles and shapes of eggs. Some have gelatinous or skin-like coverings, others have hard eggshells. Softer shells are mostly protein. It may be fibrous or quite liquid. Some arthropod eggs do not actually have shells, rather, their outer covering is actually the outermost embryonic membrane, the choroid, which serves to protect inner layers. The choroid itself can be a complex structure, and it may have different layers within it. It may have an outermost layer called an exochorion. Eggs which must survive in dry conditions usually have hard eggshells, made mostly of dehydrated or mineralized proteins with pore systems to allow respiration. Arthropod eggs can have extensive ornamentation on their outer surfaces.

　　Fish, amphibian and reptile eggs

　　Fish and amphibians generally lay eggs which are surrounded by the extraembryonic membranes but do not develop a shell, hard or soft, around these membranes. Some fish and amphibian eggs have thick, leathery coats, especially if they must withstand physical force or desiccation. These type of eggs can also be very small and fragile.

　　While many reptiles lay eggs with flexible, calcified, eggshells, there are some that lay hard eggs. Eggs laid by snakes generally have leathery shells which often adhere to one another. Depending on the species, turtles and tortoises lay hard or soft eggs. Several species lay eggs which are nearly indistinguishable from bird eggs.#p#副标题#e#

　　第三篇：

　　非洲农业发展

　　开头没读懂，后面说分为平原和高地，是不同的农业活动。一开始种植作物，后来也有畜牧业直到一种人来了。提出这里放牧is demanding(出题问原因了)herd需要喝水every 24 hours;需要吃草，冬天夏天在不同地方放牧。有一种疾病，为了躲避疾病只能小范围，小规模的畜牧业，还提到了粗放型的耕作方式，种地然后肥力耗尽以后就烧掉换下一块地。下一段也是说这种耕作方式(出题问了本段与上一段的关系)

　　解析：本文描写非洲农业的发展过程，在

　　参考阅读：

　　How did it come about that farming developed independently in a number of world centers (the Southeast Asian mainland, Southwest Asia, Central America, lowland and highland South America, and equatorial Africa) at more or less the same time? Agriculture developed slowly among populations that had an extensive knowledge of plants and animals. Changing from hunting and gathering to agriculture had no immediate advantages. To start with, it forced the population to abandon the nomad's life and become sedentary, to develop methods of storage and, often, systems of irrigation. While hunter-gatherers always had the option of moving elsewhere when the resources were exhausted, this became more difficult with farming. Furthermore, as the archaeological record shows, the state of health of agriculturalists was worse than that of their contemporary hunter-gatherers.

　　Traditionally, it was believed that the transition to agriculture was the result of a worldwide population crisis. It was argued that once hunter-gatherers had occupied the whole world, the population started to grow everywhere and food became scarce; agriculture would have been a solution to this problem. We know, however, that contemporary hunter-gatherer societies control their population in a variety of ways. The idea of a world population crisis is therefore unlikely, although population pressure might have arisen in some areas.

　　Climatic changes at the end of the glacial period 13,000 years ago have been proposed to account for the emergence of farming. The temperature increased dramatically in a short period of time (years rather than centuries), allowing for a growth of the hunting-gathering population due to the abundance of resources. There were, however, fluctuations in the climatic conditions, with the consequences that wet conditions were followed by dry ones, so that the availability of plants and animals oscillated brusquely.

　　It would appear that the instability of the climatic conditions led populations that had originally been nomadic to settle down and develop a sedentary style of life, which led in turn to population growth and to the need to increase the amount of food available. Farming originated in these conditions. Later on, it became very difficult to change because of the significant expansion of these populations. It could be argued, however, that these conditions are not sufficient to explain the origins of agriculture. Earth had experienced previous periods of climatic change, and yet agriculture had not been developed.

　　It is archaeologist Steven Mithen's thesis, brilliantly developed in his book The Prehistory of the Mind (1996), that approximately 40,000 years ago the human mind developed cognitive fluidity, that is, the integration of the specializations of the mind: technical, natural history (geared to understanding the behavior and distribution of natural resources), social intelligence, and the linguistic capacity. Cognitive fluidity explains the appearance of art, religion, and sophisticated speech. Once humans possessed such a mind, they were able to find an imaginative solution to a situation of severe economic crisis such as the farming dilemma described earlier. Mithen proposes the existence of four mental elements to account for the emergence of farming: (1) the ability to develop tools that could be used intensively to harvest and process plant resources; (2) the tendency to use plants and animals as the medium to acquire social prestige and power; (3) the tendency to develop "social relationships" with animals structurally similar to those developed with people—specifically, the ability to think of animals as people (anthropomorphism) and of people as animals (totemism); and (4) the tendency to manipulate plants and animals.

　　The fact that some societies domesticated animals and plants, discovered the use of metal tools, became literate, and developed a state should not make us forget that others developed pastoralism or horticulture (vegetable gardening) but remained illiterate and at low levels of productivity; a few entered the modern period as hunting and gathering societies. It is anthropologically important to inquire into the conditions that made some societies adopt agriculture while others remained hunter-gatherers or horticulturalists. However, it should be kept in mind that many societies that knew of agriculture more or less consciously avoided it. Whether Mithen's explanation is satisfactory is open to contention, and some authors have recently emphasized the importance of other factors.

　　第二套题

　　第一篇：

　　omlec civilization

　　讲解了奥尔梅克文明的建筑与艺术。农商业发展给艺术发展创造了适合的土壤。文章用大篇幅介绍了olmec civilization艺术的细节与特点。最后olmec艺术的影响深远，包括maya在内的文明的拉美文化深受其影响

　　解析：本文重复20140511大陆题，主要讲解的是玛雅文明的前身Olmec，在阅读理解时重点要克服学科词汇带来的阅读理解障碍。同时需要注意的是，涉及到人文历史的文章，句子都偏长，对考生的句法理解能力较高，在阅读时要小心句内关系没理清导致的丢分。

　　参考阅读：

　　The Olmec people lived in hot, humid lowlands along the Gulf Coast in what is now southern Veracruz and Tabasco states in southern Mexico. The first evidence of their remarkable art style appears at about 1200 BC in their oldest known building site, San Lorenzo. This site is remarkable for its many stone monuments, prominent among which are colossal carved heads that have characteristic flat faces and helmetlike headgear. In the late 20th century, a stone slab engraved with symbols that appear to have been the Olmec writing system was discovered in the village of Cascajal, near San Lorenzo. The Cascajal stone dates to approximately 900 BC and may be the oldest example of writing from the Americas. A later Olmec ceremonial centre, La Venta, is marked by great mounds, a narrow plaza, and several other ceremonial enclosures. In the 21st century, inscribed carvings suggestive of later Mayan glyphs also were found at La Venta.

　　The Olmecs developed a wide trading network, and between 1100 and 800 BC their cultural influence spread northwestward to the Valley of Mexico and southeastward to parts of Central America. It is clear that later Mesoamerican native religions and iconography, from all parts of the area, can be traced back to Olmec beginnings. Besides monumental architecture and sculpture, Olmec art is expressed in small jade carvings, pottery, and other media. Its dominant motif is the stylized figure of a god that is a hybrid between a jaguar and a human infant. From the Olmecs' constructions and monuments, as well as from the sophistication and power of their art, it is evident that their society was complex and nonegalitarian.

　　Olmec stylistic influence disappeared after about 400 BC. Not all of the Olmec sites were abandoned, but Olmec culture gradually changed, and the region ceased to be the cultural leader of Mesoamerica. See also Mesoamerican civilization.#p#副标题#e#

　　第二篇：

　　有一篇讲的是达尔文进化论，第一段说他出去航海，发现了gradually evolution，然后又在一片密而不大的群岛发现了很多同属T的不同species的鱼按地理分布在不同的位置 后面有一段说一种的数量迅速增加但是后来又减少(有可能记串了……)但是从另外一个社会学家?人类学家?的人说过理论结合到生物进化中(这个学家说过：曾经人口快速增长，但是食物能源供应不足，所以人口又下降了)最后部分说 达尔文觉得自己的理论没有足够多的data支持，所以没有发表，而另一个人在他之前发表了这个理论，但是最后人们觉得达尔文做的贡献数据实验XX更多，所以把他的位置优先了。

　　解析：本文讲述达尔文进化论，重复20130113大陆题。有关达尔文的理论历来就是常考内容，从经典加试到后来的各种生物相关题材。考生在阅读时要重点注意区分文中提供信息与自己的背景常识，以文中信息和观点为准。

　　参考阅读：

　　Darwin & The Galapagos Islands

　　The tiny volcanic island chain of the Galapagos has played a huge role in the formation of Charles Darwin’s ‘theory of evolution’. Darwin visited the Galapagos aboard the HMS Beagle in 1835, as part of a five year navigational mission to chart the coast of South America for the British Royal Navy. Under the command of Captain Robert Fitzroy, the expedition was drawing to a close when the Beagle landed in the Galapagos on Isla San Cristobal.

　　In his early 20’s at the time, Darwin was a young and unknown naturalist interested in joining the ministry. However, after doing extensive research and making a number of astute observations about the flora and fauna found on the four islands he had visited, Darwin became more interested in the natural sciences. He also became very keen on understanding the differences between the animal and plant species found on each of the islands, namely Isla Isabela, the Isla Floreana, the Isla Santiago and the Isla San Cristobal. He additionally noted that on each of these islands closely akin species behaved differently, which made him wonder how all of this was possible.

　　After years of endless research, he came to the conclusion which resulted in his theory of evolution by natural selection, which was published in his book The Origin of Species in 1859. Putting forward the concept that evolution and not God was responsible for the creation of human beings, Darwin shook society as we know it, to its very core. This book raised a number of important scientific questions and changed the way life was once viewed through the eyes of the church.

　　The best example of Darwin’s theory of evolution in action was explained based upon his research of the various finches found in the Galapagos. He noted that on each of the islands the finches were all slightly different from each other, with shorter or longer beaks, a different diet and fuller or less plumage. In honor of his research of these birds, the finches of the Galapagos are now known as Darwin’s finches.

　　第三篇：

　　是讲鸟叫声，male学习sing一开始不叫，冬天之前能学会，但是热带地区的female有的时候会先学会，实验室里的鸟一般在六个月内学会，而在XX地区的鸟三个月内就能学会，是因为nature pressure 鸟能学会sing是由于基因，因为deaf的鸟也能sing但是没有自己的调子，因为没有跟其他的鸟学习 鸟学习sing的方式是跟别的鸟学习，并且还会练习，比如两只小鸟都在叫“I‘m still here”在以后可以争夺领地和雌性 后面的没太看懂，好像讲的是不同地区的这种鸟会有方言，但是一开始学会的即便到另外一个地方生活，再放回来的时候还能recall 最后说给鸟听tape( ==忘了为啥了)

　　解析：本文讲解动物行为，涉及到实验相关，在TPO里有好几篇类似的文章，比如Begging by Nestlings，在理解过程中，重点抓实验结论以及不同特征的叫声所要表达的意义。

　　参考阅读：

　　Many signals that animals make seem to impose on the signalers costs that are overly damaging. A classic example is noisy begging by nestling songbirds when a parent returns to the nest with food. These loud cheeps and peeps might give the location of the nest away to a listening hawk or raccoon, resulting in the death of the defenseless nestlings. In fact, when tapes of begging tree swallows were played at an artificial swallow nest containing an egg, the egg in that “noisy” nest was taken or destroyed by predators before the egg in a nearby quiet nest in 29 of 37 trials.

　　Further evidence for the costs of begging comes from a study of differences in the begging calls of warbler species that nest on the ground versus those that nest in the relative safety of trees. The young of ground-nesting warblers produce begging cheeps of higher frequencies than do their tree-nesting relatives. These higher-frequency sounds do not travel as far, and so may better conceal the individuals producing them, who are especially vulnerable to predators in their ground nests. David Haskell created artificial nests with clay eggs and placed them on the ground beside a tape recorder that played the begging calls of either tree-nesting or of ground-nesting warblers. The eggs “advertised” by the tree-nesters' begging calls were found bitten significantly more often than the eggs associated with the ground-nesters' calls.

　　The hypothesis that begging calls have evolved properties that reduce their potential for attracting predators yields a prediction: baby birds of species that experience high rates of nest predation should produce softer begging signals of higher frequency than nestlings of other species less often victimized by nest predators. This prediction was supported by data collected in one survey of 24 species from an Arizona forest, more evidence that predator pressure favors the evolution of begging calls that are hard to detect and pinpoint.

　　Given that predators can make it costly to beg for food, what benefit do begging nestlings derive from their communications? One possibility is that a noisy baby bird provides accurate signals of its real hunger and good health, making it worthwhile for the listening parent to give it food in a nest where several other offspring are usually available to be fed. If this hypothesis is true, then it follows that nestlings should adjust the intensity of their signals in relation to the signals produced by their nestmates, who are competing for parental attention. When experimentally deprived baby robins are placed in a nest with normally fed siblings, the hungry nestlings beg more loudly than usual—but so do their better-fed siblings, though not as loudly as the hungrier birds.

　　If parent birds use begging intensity to direct food to healthy offspring capable of vigorous begging, then parents should make food delivery decisions on the basis of their offsprings’ calls. Indeed, if you take baby tree swallows out of a nest for an hour feeding half the set and starving the other half, when the birds are replaced in the nest, the starved youngsters beg more loudly than the fed birds, and the parent birds feed the active beggars more than those who beg less vigorously.

　　As these experiments show, begging apparently provides a signal of need that parents use to make judgments about which offspring can benefit most from a feeding. But the question arises, why don't nestlings beg loudly when they aren't all that hungry? By doing so, they could possibly secure more food, which should result in more rapid growth or larger size, either of which is advantageous. The answer lies apparently not in the increased energy costs of exaggerated begging—such energy costs are small relative to the potential gain in calories—but rather in the damage that any successful cheater would do to its siblings, which share genes with one another. An individual's success in propagating his or her genes can be affected by more than just his or her own personal reproductive success. Because close relatives have many of the same genes, animals that harm their close relatives may in effect be destroying some of their own genes. Therefore, a begging nestling that secures food at the expense of its siblings might actually leave behind fewer copies of its genes overall than it might otherwise.