日托福阅读真题

1、2014 年 5 月 24 日托福阅读真题智课网整理阅读词汇题：RemarkableWealthy ofDevoidCoincide withDiffusionPropagateSubsequenceInitiateChronological第一篇：苏美尔人的居住地土地贫瘠，但是每年的洪水泛滥留下了肥沃的淤泥用来耕作，由此产生了统治阶层。 而统治阶层在管理时为了记录则导致了楔形文字的产生， 后来文字应用到了社会生活中。解析： 苏美尔人（也译作苏默），是历史上两河流域（底格里斯河和幼发拉底河中下游）早期的定居民族， 他们所建立的苏美尔文明是整个美索不达米亚文明中最早， 同时也是全世界最早产生的文

2、明。 苏美尔文明主要位于美索不达米亚的南部， 通过放射性碳十四的断代测试，表明苏美尔文明的开端可以追溯至公元前 4000 年。约结束在公元前 2000 年，被闪米特人（闪族人） 建立的巴比伦所代替。 这里发现的含有楔形文字前文字的最古老的石板 （这是目前公认的最早的文字记录）可以被定期为约前 36 世纪。背景知识：Sumerian Agriculture and huntingThe Sumerians adopted an agricultural mode of life as by perhaps as early as c. 5000 - 4500 BC the region demo

3、nstrated a number of core agricultural techniques, includingorganized irrigation , large-scale intensive cultivation of land, mono-cropping involving the use of plough agriculture , and the use of an agricultural specialized labour force under bureaucratic control. The necessity to manage temple acc

4、ounts with this organization led to the development of writing (c. 3500 BC).From the royal tombs ofUr, made of lapis lazuliand shell, shows peacetimeIn the early Sumerian Uruk period, the primitive pictograms suggest thatsheep , goats ,cattle, andpigs were domesticated. They usedoxen as their primar

5、y beasts of burdenand donkeys or equids as their primary transport animal and "woollen clothing as well asrugs were made from the wool or hair of the animals. . By the side of the house was anenclosed garden planted with trees and other plants; wheat and probably other cerealswere sown in the f

6、ields, and theshaduf was already employed for the purpose of irrigation.Plants were also grown in pots or vases."An account of barley rations issued monthly to adults and children written incuneiform on clay tablet,written in year 4 of KingUrukagina , circa 2350 BCThe Sumerians practiced simila

7、r irrigation techniques as those used in Egypt. American anthropologist Robert McCormick Adams says that irrigation development was associated with urbanization, and that 89% of the population lived in the cities.Theygrew barley , chickpeas , lentils , wheat , dates , onions , garlic , lettuce , lee

8、ks and mustard .Sumerians caught many fish and huntedfowl and gazelle .Sumerian agriculture depended heavily onirrigation . The irrigation was accomplished bythe use of shaduf , canals , channels ,dykes , weirs , and reservoirs . The frequent violent floods of the Tigris , and less so, of the Euphra

9、tes , meant that canals required frequentrepair and continual removal ofsilt , and survey markers and boundary stones needed tobe continually replaced. The government required individuals to work on the canals in a corvee , although the rich were able to exempt themselves.As is known from the "

10、 Sumerian Farmer's Almanac", after the flood season and afterthe Spring Equinoxand the Akitu or New Year Festival, using the canals, farmers wouldflood their fields and then drain the water. Next they let oxen stomp the ground and killweeds. They then dragged the fields withpickaxes. After

11、drying, they plowed , harrowed ,and rakedthe ground three times, and pulverized it with amattock , before planting seed.Unfortunately the high evaporation rate resulted in a gradual increase in the salinity of thefields. By the Ur III period, farmers had switched from wheat to the moresalt-tolerantb

12、arleyas their principal crop.Sumerians harvested during thespringin three-person teams consisting of areaper ,a binder , and a sheaf handler. The farmers would usethreshing wagons , driven by oxen,to separate the cereal heads from thestalks and then use threshing sleds to disengagethe grain. They th

13、enwinnowedthe grain/chaff mixture.Language and writingMain articles:Sumerian languageand CuneiformEarly writing tablet recording the allocation of beer, 3100-3000 BCThe most important archaeological discoveries in Sumer are a large numberof tablets written incuneiform . Sumerian writing is the oldes

14、t example of writing on earth.Although pictures - that is,hieroglyphs- were first used, symbols were later made torepresent syllables. Triangular or wedge-shaped reeds were used to write on moist clay. Alarge body of hundreds of thousands of texts in the Sumerian language have survived,such as perso

15、nal or business letters, receipts,lexical lists , laws, hymns, prayers, stories,daily records, and even libraries full ofclay tablets . Monumental inscriptions and texts ondifferent objects like statues or bricks are also very common. Many texts survive inmultiple copies because they were repeatedly

16、 transcribed by scribes-in-training. Sumerian continued to be the language of religion and law in Mesopotamia long after Semitic speakers had become dominant.The Sumerian language is generally regarded as alanguage isolatein linguisticsbecauseit belongs to no known language family; Akkadian, by cont

17、rast, belongs to the Semiticbranch of theAfro-Asiatic languages. There have been many failed attempts to connectSumerian to otherlanguage groups. It is anagglutinative language; in otherwords, morphemes("units of meaning") are added together to create words,unlike analytic languageswhere m

18、orphemes are purely added together to createsentences.Understanding Sumerian texts today can be problematic even for experts. Most difficult are the earliest texts, which in many cases do not give the full grammatical structure of the language.During the 3rd millennium BC a cultural symbiosis develo

19、ped between the Sumerians andthe Akkadians, which included widespread bilingualism . The influences between Sumerian on Akkadian are evident in all areas including lexical borrowing on a massive scale-and syntactic, morphological, and phonological convergence. This mutual influence has prompted scho

20、lars to refer to Sumerian and Akkadian of the 3rd millennium BC as asprachbund .Akkadian gradually replaced Sumerian as a spoken language somewhere around the turn of the 3rd and the 2nd millennium BC, but Sumerian continued to be used as a sacred,ceremonial, literary, and scientific language in Bab

21、ylonia and Assyria until the 1st century AD.第二篇：机经：小行星对恐龙灭绝的影响。一个科学家发现土层中里有很多 Ir 元素，而 Ir 元素在地球上少见，因此推断是小行星导致了恐龙灭绝。 后面又说了小行星使得气温降低， 空气化学组成改变等等也导致恐龙的灭绝，但是一些小的啮齿类动物则存活了下来。解析： 在恐龙绝灭假说中，小行星撞击说最为流行。此说认为，小行星（后有学者认为 彗星的可能性更大）才是杀死恐龙的罪魁祸首。小行星撞击说是 1979 年由美国物理学家阿尔瓦雷斯等人提出的。他们认为， 6500 万年前的一颗直径约为 10 公里的小行星与 地球 相撞，

22、发生猛烈大爆炸，大量尘埃抛入大气层中，致使数月之内阳光被遮挡，大地一片黑暗寒冷，植物枯死，食物链中断，包括恐龙在内的很多动物绝灭。参考文章： Meteorite Impact and Dinosaur ExtinctionExtinction of the DinosaursMass Extinctions背景知识：Impact eventBiospheric effectsThe effect of impact events on the biosphere has been the subject of scientific debate. Several theories of imp

23、act related mass extinction have been developed. In the past 500million years there have been five generally accepted, majormass extinctionsthat onaverage extinguished half of allspecies . One of the largest mass extinction to haveaffected life on Earth was in thePermian-Triassic , which ended thePe

24、rmianperiod 250million years ago and killed off 90% of all species; life on Earth took 30 million years torecover. The cause of the Permian-Triassic extinction is still matter of debate with the ageand origin of proposed impact craters, i.e. theBedoutHigh structure, hypothesized to beassociated with

25、 it are still controversial. The last such mass extinction led to the demise ofthe dinosaursand coincided with a largemeteoriteimpact; this isthe CretaceousPaleogene extinction event(also known as the KT or K Pg extinctionevent); This occurred 66 million years ago. There is no definitive evidence of

26、 impactsleading to the three other majormass extinctions .In 1980, physicistLuis Alvarez; his son, geologistWalter Alvarez ; and nuclear chemistsFrank Asaro and Helen V. Michael from theUniversity of California, Berkeleydiscoveredunusually high concentrations ofiridium in a specific layer of rockstr

27、ata in the Earth'scrust. Iridium is an element that is rare on Earth but relatively abundant inmany meteorites. From the amount and distribution of iridium present in the65-million-year-old "iridium layer", the Alvarez team later estimated that an asteroid of 10to 14 km (6 to 9 mi) mus

28、t have collided with the earth. This iridium layer atthe CretaceousPaleogene boundary has been found worldwide at 100 different sites.Multidirectionallyshocked quartz(coesite), which is only known to form as the result oflarge impacts oratomic bombexplosions, has also been found in the same layer at

29、 morethan 30 sites.Soot and ash at levels tens of thousands times normal levels were foundwith the above.Anomalies in chromium isotopic ratios found within the K-T boundary layer strongly support the impact theory. Chromium isotopic ratios are homogeneous within the earth, therefore these isotopic a

30、nomalies exclude a volcanic origin which was also proposed as a cause for the iridium enrichment. Furthermore the chromium isotopic ratios measured inthe K-T boundary are similar to the chromium isotopic ratios found in carbonaceous chondrites . Thus a probable candidate for the impactor is a carbon

31、aceous asteroid but also a comet is possible because comets are assumed to consist of material similar to carbonaceous chondrites.Probably the most convincing evidence for a worldwide catastrophe was the discovery ofthe crater which has since been namedChicxulub Crater. This crater is centered on th

32、eYucat án Peninsula of Mexico and was discovered by Tony Camargo and Glen Pentfieldwhile working asgeophysicistsfor the Mexican oil companyPEMEX . What they reportedas a circular feature later turned out to be a crater estimated to be 180 km (110 mi) indiameter. Other researchers would later fi

33、nd that the end-Cretaceousextinction eventthatwiped out the dinosaurs had lasted for thousands of years instead of millions of years as had previously been thought. This convinced the vast majority of scientists that thisextinction resulted from a point event that is most probably an extraterrestria

34、l impact and not from increased volcanism and climate change (which would spread its main effect over a much longer time period).Recently, several proposed craters around the world have been dated to approximatelythe same age as Chicxulub for example, theSilverpit craterin the United Kingdom,the Bol

35、tysh craterin Ukraine and theShiva craternear India. This has led to thesuggestion that the Chicxulub impact was one of several that occurred almostsimultaneously, perhaps due to a disruptedcomet impacting the Earth in a similar mannerto the collision ofComet Shoemaker-Levy 9with Jupiter in 1994; ho

36、wever, the uncertainage and provenance of these structures leaves the hypothesis without widespread support.It was the lack of high concentrations of iridium and shocked quartz which has prevented the acceptance of the idea that the Permian extinction was also caused by an impact. During the late Pe

37、rmian all the continents were combined into one supercontinentnamed Pangaea and all the oceans formed one superocean, Panthalassa . If an impact occurred in the ocean and not on land at all, then there would be little shocked quartz released (since oceanic crust has relatively little silica ) and mu

38、ch less material.Although there is now general agreement that there was a huge impact at the end of the Cretaceous that led to the iridium enrichment of the K-T boundary layer, remnants have been found of other, smaller impacts, some nearing half the size of the Chicxulub crater, which did not resul

39、t in any mass extinctions, and there is no clear linkage between an impact and any other incident of mass extinction.PaleontologistsDavid M. Raupand Jack Sepkoskihave proposed that an excess ofextinction events occurs roughly every 26 million years (though many are relatively minor).This led physici

40、stRichard A. Mullerto suggest that these extinctions could be due to ahypothetical companion star to the Sun calledNemesisperiodically disrupting the orbits ofcomets in theOort cloud , and leading to a large increase in the number of cometsreaching the inner solar system where they might hit Earth.

41、PhysicistAdrian MelottandpaleontologistRichard Bambachhave more recently verified the Raup and Sepkoskifinding, but argue that it is not consistent with the characteristics expected of a Nemesis-style periodicity.第三篇：机经：冰河时期形成原因第一段：地球周期一直被人们观测。但直到科学家M，才提出是地球的orbit三个因素共同发生造成的。 Eccentric, tilt and orb

42、it. 。第二段：三个理论。 【好长一段】第三段：三个角度变化要好多年。周期不能解释。第四段：还有好多其他解释，有人说火山，有人说 有人说解析： 冰期地球表面覆盖有大规模冰川的地质时期。又称为冰川时期。两次冰期之间唯一相对温暖时期，称为间冰期。地球历史上曾发生过多次冰期，最近一次是第四纪冰期。地球在 40 多亿年的历史中， 曾出现过多次显著降温变冷，形成冰期。特别是在前寒武纪晚期、石炭纪至二叠纪和新生代的冰期都是持续时间很长的地质事件，通常称为大冰期。大冰期的时间尺度至少数百万年。大冰期内又有多次大幅度的气候冷暖交替和冰盖规模的扩展或退缩时期，这种扩展和退缩时期即为冰期和间冰期。学者们提出过种

43、种解释， 但至今没有得到令人感到满意的答案。 归纳起来， 主要有天文学和地球物理学成因说。天文学成因说天文学成因说主要考虑太阳、其他行星与地球间的相互关系。太阳光度的周期变化影响地球的气候。太阳光度处于弱变化时，辐射量减少，地球变冷，乃至出现冰期气候。米兰科维奇认为， 夏半年太阳辐射量的减少是导致冰期发生的可能因素。地球黄赤交角的周期变化导致气温的变化。黄赤交角指黄道与天赤道的交角，它的变化主要受行星摄动的影响。当黄赤交角大时，冬夏差别增大，年平均日射率最小，使低纬地区处于寒冷时期，有利于冰川生成。地球物理学成因说地球物理学成因说影响因素较多，有大气物理方面的，也有地理地质方面的。大气透明度的

44、影响。频繁的火山活动等使大气层饱含着火山灰，透明度低，减少了太阳辐射量，导致地球变冷。构造运动的影响。构造运动造成陆地升降、陆块位移、视极移动，改变了海陆分布和环流型式，可使地球变冷。云量、蒸发和冰雪反射的反馈作用，进一步使地球变冷，促使冰期来临。大气中CO2的屏蔽作用。 CO2能阻止或减低地表热量的损失。如果大气中 CO2含量增加到今天的23 倍，则极地气温将上升89；如果今日大气中的CO2含量减少 5560%，则中纬地带气温将下降45。在地质时期火山活动和生物活动使大气圈中CO2含量有很大变化，当CO2屏蔽作用减少到一定程度，则可能出现冰期。背景知识：An ice ageis a peri

45、od of long-term reduction in thetemperatureof the Earth 's surface andatmosphere,resulting inthepresenceorexpansionofcontinentalandpolaricesheets and alpineglaciers . Within a long-term ice age, individual pulses of cold climateare termed "glacial periods" (or alternatively "glaci

46、als" or "glaciations" or colloquially as"iceage"),andintermittentwarmperiodsare called"interglacials ".Glaciologically, iceage impliesthepresenceofextensiveicesheets in thenorthernandsouthernhemispheres. By this definition, we are in an interglacial period - thehol

47、ocene , of the iceagethat began2.6 millionyearsago atthestart ofthe Pleistoceneepoch,becausethe Greenland , Arctic , and Antarctic ice sheetsstill exist.Variations in Earth's orbit (Milankovitch cycles)The Milankovitch cycles are a set of cyclic variations in characteristics of the Earth's o

48、rbit around the Sun. Each cycle has a different length, so at some times their effects reinforce each other and at other times they (partially) cancel each other.Past and future of daily average insolation at top of the atmosphere on the day of the summer solstice, at65 N latitude.There is strong ev

49、idence that the Milankovitch cycles affect the occurrence of glacial and interglacial periods within an ice age. The present ice age is the most studied and bestunderstood, particularly the last 400,000 years, since this is the period covered byicecores that record atmospheric composition and proxie

50、s for temperature and ice volume. Within this period, the match of glacial/interglacial frequencies to the Milankovi? orbital forcing periods is so close that orbital forcing is generally accepted. The combined effectsof the changing distance to the Sun, the precession of the Earth'saxis , and t

51、he changingtilt of the Earth's axis redistribute the sunlight received by the Earth. Of particularimportance are changes in the tilt of the Earth's axis, which affect the intensity ofseasonsFor example, the amount of solar influx in July at65 degrees northlatitude varies by as.much as 22% (f

52、rom 450 W/m2 to 550 W/m2 ). It is widely believed that ice sheets advance when summers become too cool to melt all of the accumulated snowfall from the previous winter. Some workers believe that the strength of the orbital forcing is too small to triggerglaciations, but feedback mechanisms like CO2

53、may explain this mismatch.While Milankovitch forcing predicts that cyclic changes in the Earth'sorbital elements canbe expressed in the glaciation record, additional explanations are necessary to explainwhich cycles are observed to be most important in the timing of glacialinterglacial periods.I

54、n particular, during the last 800,000 years, the dominant period of glacialinterglacialoscillation has been 100,000 years, which corresponds tochangesin Earth's orbitaleccentricity and orbital inclination . Yet this is by far the weakest of the three frequenciespredicted by Milankovitch. During

55、the period 3.00.8 million years ago, the dominantpattern of glaciation corresponded to the 41,000-year period of changes inEarth's obliquity (tilt of the axis). The reasons for dominance of one frequency versus another are poorly understood and an active area of current research, but the answer pro