托福TPO35阅读Passage2原文文本+题目+答案解析
托福TPO34阅读Passage2原文文本+题目+答案解析
托福TPO34阅读Passage2原文文本+题目+答案解析为了帮助大家高效备考托福，为大家带来托福TPO34阅读Passage2原文文本+题目+答案解析，希望对大家备考有所帮助。
The Development of Steam Power蒸汽机的发展By the eighteenth century,Britain was experiencing a severe shortage of energy.Because of the growth of population,most of the great forests of medieval Britain had long ago been replaced by fields of grain and hay.Wood was in ever-shorter supply,yet it remained tremendously important.It served as the primary source of heat for all homes and industries and as a basic raw material.Processed wood(charcoal)was the fuel that was mixed with iron ore in the blast furnace to produce pig iron(raw iron).The iron industry’s appetite for wood was enormous,and by 1740 the British iron industry was stagnating.Vast forests enabled Russia to become the world’s leading producer of iron,much of which was exported to Britain.But Russia’s potential for growth was limited too,and in a few decades Russia would reach the barrier of inadequate energy that was already holding England back.在18世纪之前，英国正在经历一次严重的能源短缺。
2021年托福阅读PASSAGE 35 试题及答案
2021年托福阅读PASSAGE 35试题及答案PASSAGE 35The observation of the skies has played a special part in the lives and cultures of peoples since the earliest of times. Evidence obtained from a site known as the Hole in the Rock, in Papago Park in Phoenix, Arizona, indicates that it might have been used as an observatory by a prehistoric people known as the Hohokam.The physical attributes of the site allow its use as a natural calendar/clock. The "hole" at Hole in the Rock is formed by two large overhanging rocks coming together at a point, creating a shelter with an opening large enough for several persons to pass through. The northeast-facing overhang has a smaller opening in its roof. It is this smaller hole that produces the attributes that may have been used as a calendar/clock. Because of its location in the shelter's roof, a beam of sunlight can pass through this second hole and cast a spot onto the shelter's wall and floor. This spot of light travels from west to east as the sun moves across the sky. It also moves from north to south and back again as the Earth travels around the Sun, the west-to-east movement could have been used to establish a daily clock, much like a sundial, while the north-to-south movement could have been used to establish a seasonal calendar.The spot first appears and starts down the surface of the wall of the shelter at different times of the morning depending on the time of the year. The spot grows in size from its first appearance until its maximum size is achieved roughly at midday. It then continues its downward movement until it reaches a point where it jumps to the floor of the shelter. As the Sun continues to move to the west, the spot continues to move across the shelter floor and down the butte, or hill, toward a group of small boulders. If a person is seated on a certain one of these rocks as the spot reaches it, the Sun can be viewed through the calendar hole. This occurs at different times in the afternoon depending on the time of year.1. What does the passage mainly discuss?(A) observations of the stars by ancient people(B) rock formations of Arizona(C) a site used by ancient people to measure time(D) the movement of the earth around the Sun2. The word "obtained" in line 2 is closest in meaning to(A) acquired(B) transported(C) covered(D) removed3. The word "attributes" in line 5 is closest in meaning to(A) changes(B) characteristics(C) locations(D) dimensions4. The word "its" in line 10 refers to(A) roof(B) beam(C) hole(D) spot5. The word "establish" in line 15 is closest in meaning to(A) create(B) locate(C) consult(D) choose6. Which of the following is NOT true of the spot of light?(A) It is caused by sunlight passing through a hole.(B) It travels across the roof of the shelter.(C) Its movement is affected by the position of the Sun.(D) It movement could have been used to estimate the time of day.7. From which of the following can be the time of year be determined?(A) The movement of the spot of light from west to east(B) The speed with which the spot of light moves(C) The movement of the spot of light from north to south(D) The size of the sport of light at midday8. The word "roughly" in line 18 is closest in meaning to(A) finally(B) harshly(C) uneasily(D) approximately9. The passage mentions that the Hole in the Rock was used as all of the following EXCEPT(A) a calendar(B) a home(C) a clock(D) an observatory10. Which of the following can be inferred from the fourth paragraph?(A) The boulders are located below the rock shelter.(B) The person seated on the rock cannot see the shelter.(C) After it passes the boulders, the spot of light disappears.(D) The spot of light is largest when it first appears.ANSWER KEYSPASSAGE 35 CABCA BCDBA。
托福TPO35阅读Passage3原文文本+题目+答案解析
为了帮助大家高效备考托福，为大家带来托福TPO35阅读Passage3原文文本+题目+答案解析，希望对大家备考有所帮助。
The surface of Mars [1]The surface of Mars shows a wide range of geologic features,including huge volcanoes—the largest known in the solar system—and extensive impact cratering.Three very large volcanoes are found on the Tharsis bulge,an enormous geologic area near Mars's equator.Northwest of Tharsis is the largest volcano of all:Olympus Mons,with a height of 25 kilometers and measuring some 700 kilometers in diameter at its base.The three large volcanoes on the Tharsis bulge are a little smaller—a“mere”18 ki1ometers high. [2]None of these volcanoes was formed as a result of collisions between plates of the Martian crust-there is no plate motion on Mars.Instead,they are shield volcanoes—volcanoes with broad,sloping slides formed by molten rock.All four show distinctive lava channels and other flow features similar to those found on shield volcanoes on Earth.Images of the Martian surface reveal many hundreds of volcanoes.Most of the largest volcanoes are associated with the Tharsis bulge,but many sma11er ones are found in the northern plains. [3]The great height of Martian volcanoes is a direct consequence of the planet's low surface gravity.As lava flows and spreads to form a shield volcano,the volcano's eventual height depends on the new mountain's ability to support its own weight.The lower the gravity,the lesser the weight and the greater the height of the mountain.It is no accident that Maxwell Mons on Venus and the Hawaiian shield volcanoes on Earth rise to about the same height(about10 kilometers)above their respective bases-Earth and Venus have similar surface gravity.Mars's surface gravity is only 40 percent that of Earth,so volcanoes rise roughly 2.5 times as high.Are the Martian shield volcanoes still active?Scientists have no direct evidence for recent or ongoing eruptions,but if these volcanoes were active as recently as 100 million years ago(an estimate of the time of last eruption based on the extent of impact cratering on their slopes),some of them may still be at least intermittently lions of years,though,may pass between eruptions. [4]Another prominent feature of Mars's surface is cratering.The Mariner spacecraft found that the surface of Mars,as well as that of its two moons,is pitted with impact craters formed by meteoroids falling in from space.As on our Moon,the smaller craters are often filled with surface matter—mostly dust—confirming that Mars is a dry desert world.However,Martian craters get filled in considerably faster than their lunar counterparts.On the Moon,ancient craters less than100 meters across(corresponding to depths of about 20 meters)have been obliterated,primarily by meteoritic erosion.On Mars,there are relatively few craters less than 5 kilometers in diameter.The Martian atmosphere is an efficient erosive agent,with Martian windstransporting dust from place to place and erasing surface features much faster than meteoritic impacts alone can obliterate them. [5]As on the Moon,the extent of large impact cratering(i.e.craters too big to have been filled in by erosion since they were formed)serves as an age indicator for the Martian surface.Age estimates ranging from four billion years for Mars's southern highlands to a few hundred million years in the youngest volcanic areas were obtained in this way. [6]The detailed appearance of Martian impact craters provides an important piece of information about conditions just below the planet's surface.Martian craters are surrounded by ejecta(debris formed as a result of an impact)that looks quite different from its lunar counterparts.A comparison of the Copernicus crater on the Moon with the(fairly typical)crater Yuty on Mars demonstrates the differences.The ejecta surrounding the lunar crater is just what one would expect from an explosion ejecting a large volume of dust,,soil,and boulders.■However,the ejecta on Mars gives the distinct impression of a liquid that has splashed or flowed out of crater.■Geologists think that this fluidized ejecta crater indicates that a layer of permafrost,or water ice,lies just a few meters under the surface.■Explosive impacts heated and liquefied the ice,resulting in the fluid appearance of the ejecta.■ Paragraph 1 Q29 The word“enormous”in the passage is closest in meaning to A.Important B.Extremely large C.Highly unusual D.Active 正确答案:B 解析：回到原文题干定位词汇出现的句子，“Three very large volcanoes are found on the Tharsis bulge,an enormous geologic area near Mars’s equator.”从句型结构来看，这句话的是修饰Tharsis bulge的同位语短语。
托福TPO30阅读Passage2原文文本+题目+答案解析
托福TPO30阅读Passage2原文文本+题目+答案解析为了帮助大家高效备考托福，为大家带来托福TPO30阅读Passage2原文文本+题目+答案解析，希望对大家备考有所帮助。
The Pace of Evolutionary ChangeA heated debate has enlivened recent studiesof evolution.Darwin's original thesis,and theviewpoint supported by evolutionary gradualists,isthat species change continuously but slowly and insmall increments.Such changes are all but invisible over the short time scale of modernobservations,and,it is argued,they are usually obscured by innumerable gaps in theimperfect fossil record.Gradualism,with its stress on the slow pace of change,is a comfortingposition,repeated over and over again in generations of textbooks.By the early twentiethcentury,the question about the rate of evolution had been answered in favor of gradualism tomost biologists'satisfaction.最近的一个关于进化的研究引发了激烈的争论。
达尔文的原始论点和进化渐进主义者支持的观点是物种会持续地改变，但非常缓慢，增量也很小。
托福阅读tpo53R-2原文+译文+题目+答案+背景知识
托福阅读tpo53R-2Rain Forest Soils原文 (1)译文 (2)题目 (3)答案 (8)背景知识 (9)原文Rain Forest Soils①On viewing the lush plant growth of a tropical rain forest,most people would conclude that the soil beneath it is rich in nutrients.However,although rain forest soils are highly variable,they have in common the fact that abundant rainfall washes mineral nutrients out of them and into streams.This process is known as leaching.Because of rain leaching,most tropical rain forest soils have low to very low mineral nutrient content,in dramatic contrast to mineral-rich grassland soils. Tropical forest soils also often contain particular types of clays that,unlike the mineral-binding clays of temperate forest soils,do not bind mineral ions well. Aluminum is the dominant cation(positively charged ion)present in tropical soils; but plants do not require this element,and it is moderately toxic to a wide range of plants.Aluminum also reduces the availability of phosphorus,an element in high demand by plants.②High moisture and temperatures speed the growth of soil microbes that decompose organic compounds,so tropical soils typically contain far lower amounts of organic materials(humus)than do other forest or grassland soils. Because organic compounds help loosen compact clay soils,hold water,and bind mineral nutrients,the relative lack of organic materials in tropical soils is deleterious to plants.Plant roots cannot penetrate far into hard clay soils,and during dry periods,the soil cannot hold enough water to supply plant needs. Because the concentration of dark-colored organic materials is low in tropical soils, they are often colored red or yellow by the presence of iron,aluminum:and manganese oxides;when dry,these soils become rock hard.The famous Cambodian temples of Angkor Wat,which have survived for many centuries,were constructed from blocks of such hard rain forest soils.③Given such poor soils,how can lush tropical forests exist?The answer is that the forest's minerals are held in its living biomass—the trees and other plants and theanimals.In contrast to grasslands,where a large proportion of plant biomass is produced underground,that of tropical forests is nearly all aboveground.Dead leaves,branches,and other plant parts,as well as the wastes and bodies of rain forest animals,barely reach the forest floor before they are rapidly decayed by abundant decomposers—bacterial and fungal.Minerals released by decay are quickly absorbed by multitudinous shallow,fine tree feeder roots and stored in plant tissues.Many tropical rain forest plants(like those in other forests)have mycorrhizal(fungus-root)partners whose delicate hyphae spread through great volumes of soil,from which they release and absorb minerals and ferry them back to the host plant in exchange for needed organic compounds.The fungal hyphae are able to absorb phosphorus that plant roots could not themselves obtain from the very dilute soil solutions,and fungal hyphae can transfer mineral nutrients from one forest plant to another.Consequently,tropical rain forests typically have what are known as closed nutrient systems,in which minerals are handed off from one organism to another with little leaking through to the soil.When mineral nutrients do not spend much time in the soil,they cannot be leached into streams. Closed nutrient systems have evolved in response to the leaching effects of heavy tropical rainfall.Evidence for this conclusion is that nutrient systems are more open in the richest tropical soils and tightest in the poorest soils.④The growth of organisms is dependent on the availability of nutrients,none of which is more important than nitrogen.Although there is an abundant supply of nitrogen in Earth’s atmosphere,it cannot be absorbed by plants unless it is“fixed,”or combined chemically with other elements to form nitrogen compounds. Nitrogen-fixing bacteria help tropical rain forest plants cope with the poor soils there by supplying them with needed nitrogen.Many species of tropical rain forest trees belong to the legume family,which is known for associations of nitrogen-fixing bacteria within root nodules.Also,cycads(a type of tropical plant that resembles a palm tree)produce special aboveground roots that harbor nitrogen-fixing cyanobacteria.By growing above the ground,the roots are exposed to sunlight,which the cyanobacteria require for growth.Nitrogen fixation by free-living bacteria in tropical soils is also beneficial.译文热带雨林土壤①在观察热带雨林茂盛的植物生长时，大多数人会得出这样的结论：雨林下面的土壤营养丰富。
托福TPO35阅读Passage1原文文本+题目+答案解析
为了帮助大家高效备考托福，为大家带来托福TPO35阅读Passage1原文文本+题目+答案解析，希望对大家备考有所帮助。
Memphis:United Egypt's First Capital [1]The city of Memphis,located on the Nile near the modern city of Cairo,was founded around 3100 B.C.as the first capital of a recently united Egypt.The choice of Memphis by Egypt's first kings reflects the site's strategic importance.■First,and most obvious,the apex of the Nile River delta was a politically opportune location for the state's administrative center,standing between the united lands of Upper and Lower Egypt and offering ready access to both parts of the country.The older predynastic(pre-3100BC)centers of power,This and Hierakonpolis,were too remote from the vast expanse of the delta,which had been incorporated into the united state.■Only a city within easy reach of both the Nile valley to the south and the more spread out,difficult terrain to the north could provide the necessary political control that the rulers of early dynastic Egypt(roughly 3000-2600 B.C.)required.■ [2]The region of Memphis must have also served as an important node for transport and communications,even before the unification of Egypt.The region probably acted as a conduit for much,if not all,of the river-based trade between northern and southern Egypt.■Moreover,commodities(such as wine,precious oils,and metals)imported from the Near East by the royal courts of predynastic Upper Egypt would have been channeled through the Memphis region on their way south.In short,therefore,the site of Memphis offered the rulers of the Early Dynastic Period an ideal location for controlling internal trade within their realm,an essential requirement for a state-directed economy that depended on the movement of goods. [3]Equally important for the national administration was the ability to control communications within Egypt.The Nile provided the easiest and quickest artery of communication,and the national capital was,again,ideally located in this respect.Recent geological surveys of the Memphis region have revealed much about its topography in ancient times.It appears that the location of Memphis may have been even more advantageous for controlling trade,transport,and communications than was previously appreciated.Surveys and drill cores have shown that the level of the Nile floodplain has steadily risen over the last five millenniums.When the floodplain was much lower,as it would have been in predynastic and early dynastic times,the outwash fans(fan-shaped deposits of sediments)of various wadis(stream-beds or channels that carry water only during rainy periods)would have been much more prominent features on the east bank.The fan associated with the Wadi Hof extended a significant way into the Nile floodplain,forming a constriction in the vicinity of Memphis.The valley may have narrowed at this point to a mere three kilometers,making it the ideal place for controlling river traffic. [4]Furthermore,the Memphis region seems to have been favorably located for thecontrol not only of river-based trade but also of desert trade routes.The two outwash fans in the area gave access to the extensive wadi systems of the eastern desert.In predynastic times,the Wadi Digla may have served as a trade route between the Memphis region and the Near East,to judge from the unusual concentration of foreign artifacts found in the predynastic settlement of Maadi.Access to,and control of,trade routes between Egypt and the Near East seems to have been a preoccupation of Egypt's rulers during the period of state formation.The desire to monopolize foreign trade may have been one of the primary factors behind the political unification of Egypt.The foundation of the national capital at the junction of an important trade route with the Nile valley is not likely to have been accidental.Moreover,the Wadis Hof and Digla provided the Memphis region with accessible desert pasturage.As was the case with the cities of Hierakonpolis and Elkab,the combination within the same area of both desert pasturage and alluvial arable land(land suitable for growing crops)was a particularly attractive one for early settlement;this combination no doubt contributed to the prosperity of the Memphis region from early predynastic times. 1.The word"trivial"in the passage is closest in meaning to A.similar B.inaccurate C.small D.significant Paragraph 1 is marked with? 答案： C选项正确 解析： 本题为词汇题，根据所给单词trivial定位到第一段More important than the amount of time Herodotus computed,which turns out to be trivial compared with the age of Earth,was the notion that one could estimate ages of geologic features by determining rates of the processes responsible for such features,and then assuming the rates to be roughly constant over time.本句大致意思为：与地球的年龄相比，Herodotus这个人计算出来的时间量是trivial的，与其相比更重要的是一个概念，这个概念是一个人可以通过估计相应地理特征的某种过程的速度来估计地理特征的年龄……再以Herodotus为关键词定位这个time是什么，找到本段第三句，发现他是推测Nile Delta花了几千年形成的。
托福TPO35听力Conversation2文本+题目+答案解析
为了帮助大家高效备考托福，为大家带来托福TPO35听力Conversation2文本+题目+答案解析，希望对大家备考有所帮助。
托福TPO35听力Conversation2文本 Narrator: Listen to a conversation between a student and his European History Professor. Professor: So I wanted to talk about your outline. I do like your topic: William, the conqueror, leading the Norman invasion of England. But I'm a little concerned about your source and the fact that you want to use it as the entire basis of your paper. Student: Really? The Bayeux tapestry? I thought it was pretty creative to use something that was made to hang on a wall as a source. And as far as I know it's the most important documentation of the invasion, a first-hand account, right? Professor: Well, you are right. It's considered a primary source. And at 70 meters long, the tapestry certainly is impressive. Imagine the time it took for those embroiderers to sew all those words and images to tell the story of the Norman forces sailing from France to England. So, yeah, it's an amazing artifact, but what’s problematic is that the tapestry is a very controversial source. Were you aware of this? Student: Well, I know some pieces of it were probably lost. Professor: It is incomplete, but... Student: But I also read that historians have relied on it to help interpret the events leading up to the invasion and the battle itself. Professor: Well, it has great historical value, no doubt, but in my opinion, there's a problem because...well...do you know who commissioned the tapestry? Student: It was a church official...um...the bishop of Bayeux, a city in France? Professor: Yes. And the bishop was also William the Conqueror's half-brother. Student: Oh! That I didn't know. But regardless of who commissioned it, isn't the fact that it was based on eye witness accounts the most important thing? I mean, it was made only 17 years after the battle. So plenty of eye witnesses were still alive. Professor: Yes, that's true. But the real point of the controversy isn't thebattle itself. It has to do with the reason for the battle: who was the rightful heir to the throne? Who would be the next king? And if William the Conqueror's brother is the one who's commissioned this tapestry... Student: Then he would be the one to decide which words and images would go on the tapestry and what would be left out. Professor:Exactly. So of course the tapestry shows why William should be the new king. Student:I guess I see your point. Embroiderers are just gonna do what they are told to do. Professor:You have to understand that the tapestry depicted an entire series of events as they were interpreted by the Normans, the victors of the battle. And that's a problem if you are trying to write objectively about the invasion, especially if you use it as your only source of information. After all, it's important for historians to examine an event from all sides. 托福TPO35听力Conversation2题目 1.Why does the professor want to talk to the student? A. To review material from a previous class. B. To recommend a resource for an assignment. C. To outline steps the student should take to complete his research. D. To discuss the student's plan for a paper. 2.What does the professor imply about the student's outline? A. It needs to have a clearer thesis. B. It needs to include specific examples. C. It needs to have information from additional sources. D. It needs to be better organized. 3.According to the student, why is the Bayeux Tapestry an important historical document?。
托福TPO3阅读Passage2原文文本+题目+答案解析
为了帮助大家高效备考托福，为大家带来托福TPO3阅读Passage2原文文本+题目+答案解析，希望对大家备考有所帮助。
▉托福TPO3阅读Passage2原文文本： Depletion of the Ogallala Aquifer The vast grasslands of the High Plains in the central United States were settled by farmers and ranchers in the 1880s. This region has a semiarid climate, and for 50 years after its settlement, it supported a low-intensity agricultural economy of cattle ranching and wheat farming. In the early twentieth century, however, it was discovered that much of the High Plains was underlain by a huge aquifer (a rock layer containing large quantities of groundwater). This aquifer was named the Ogallala aquifer after the Ogallala Sioux Indians, who once inhabited the region. The Ogallala aquifer is a sandstone formation that underlies some 583,000 square kilometers of land extending from northwestern Texas to southern South Dakota. Water from rains and melting snows has been accumulating in the Ogallala for the past 30,000 years. Estimates indicate that the aquifer contains enough water to fill Lake Huron, but unfortunately, under the semiarid climatic conditions that presently exist in the region, rates of addition to the aquifer are minimal, amounting to about half a centimeter a year. The first wells were drilled into the Ogallala during the drought years of the early 1930s. The ensuing rapid expansion of irrigation agriculture, especially from the 1950s onward, transformed the economy of the region. More than 100,000 wells now tap the Ogallala. Modern irrigation devices, each capable of spraying 4. 5 million liters of water a day, have produced a landscape dominated by geometric patterns of circular green islands of crops. Ogallala water has enabled the High Plains region to supply significant amounts of the cotton, sorghum, wheat, and corn grown in the United States. In addition, 40 percent of American grain-fed beef cattle are fattened here. This unprecedented development of a finite groundwater resource with an almost negligible natural recharge rate—that is, virtually no natural water source to replenish the water supply—has caused water tables in the region to fall drastically. In the 1930s, wells encountered plentiful water at a depth of about 15 meters; currently, they must be dug to depths of 45 to 60 meters or more. In places, the water table is declining at a rate of a meter a year, necessitating the periodic deepening of wells and the use of ever-more-powerful pumps. It is estimated that at current withdrawal rates, much of the aquifer will run dry within 40 years. The situation is most critical in Texas, where the climate is driest, the greatest amount of water is being pumped, and the aquifer contains the least water. It is projected that the remaining Ogallala water will, by the year 2030, support only 35 to 40 percent ofthe irrigated acreage in Texas that is supported in 1980. The reaction of farmers to the inevitable depletion of the Ogallala varies. Many have been attempting to conserve water by irrigating less frequently or by switching to crops that require less water. Others, however, have adopted the philosophy that it is best to use the water while it is still economically profitable to do so and to concentrate on high-value crops such as cotton. The incentive of the farmers who wish to conserve water is reduced by their knowledge that many of their neighbors are profiting by using great amounts of water, and in the process are drawing down the entire region’s water supplies. In the face of the upcoming water supply crisis, a number of grandiose schemes have been developed to transport vast quantities of water by canal or pipeline from the Mississippi, the Missouri, or the Arkansas rivers. Unfortunately, the cost of water obtained through any of these schemes would increase pumping costs at least tenfold, making the cost of irrigated agricultural products from the region uncompetitive on the national and international markets. Somewhat more promising have been recent experiments for releasing capillary water (water in the soil) above the water table by injecting compressed air into the ground. Even if this process proves successful, however, it would almost triple water costs. Genetic engineering also may provide a partial solution, as new strains of drought-resistant crops continue to be developed. Whatever the final answer to the water crisis may be, it is evident that within the High Plains, irrigation water will never again be the abundant, inexpensive resource it was during the agricultural boom years of the mid-twentieth century. ▉托福TPO3阅读Passage2题目： Question 1 of 14 According to paragraph 1, which of the following statements about the High Plains is true? A. Until farmers and ranchers settled there in the 1880s, the High Plains had never been inhabited.. B. The climate of the High Plains is characterized by higher-than-average temperatures.. C. The large aquifer that lies underneath the High Plains was discovered by the Ogallala Sioux Indians.. D. Before the early 1900s there was only a small amount of farming and ranching in the High Plains..。
tpo35三篇阅读原文译文题目答案译文背景知识
tpo35三篇阅读原文译文题目答案译文背景知识阅读-1 (1)原文 (2)译文 (5)题目 (8)答案 (17)背景知识 (18)阅读-2 (21)原文 (21)译文 (24)题目 (27)答案 (36)背景知识 (36)阅读-3 (39)原文 (39)译文 (43)题目 (46)答案 (54)背景知识 (55)阅读-1原文Earth’ s Age①One of the first recorded observers to surmise a long age for Earth was the Greek historian Herodotus, who lived from approximately 480 B.C. to 425 B.C. He observed that the Nile River Delta was in fact a series of sediment deposits built up in successive floods. By noting that individual floods deposit only thin layers of sediment, he was able to conclude that the Nile Delta had taken many thousands of years to build up. More important than the amount of time Herodotus computed, which turns out to be trivial compared with the age of Earth, was the notion that one could estimate ages of geologic features by determining rates of the processes responsible for such features, and then assuming the rates to be roughly constant over time. Similar applications of this concept were to be used again and again in later centuries to estimate the ages of rock formations and, in particular, of layers of sediment that had compacted and cemented to form sedimentary rocks.②It was not until the seventeenth century that attempts were madeagain to understand clues to Earth's history through the rock record. Nicolaus Steno (1638-1686) was the first to work out principles of the progressive depositing of sediment in Tuscany. However, James Hutton (1726-1797), known as the founder of modern geology, was the first to have the important insight that geologic processes are cyclic in nature. Forces associated with subterranean heat cause land to be uplifted into plateaus and mountain ranges. The effects of wind and water then break down the masses of uplifted rock, producing sediment that is transported by water downward to ultimately form layers in lakes, seashores, or even oceans. Over time, the layers become sedimentary rock. These rocks are then uplifted sometime in the future to form new mountain ranges, which exhibit the sedimentary layers (and the remains of life within those layers) of the earlier episodes of erosion and deposition.③Hutton's concept represented a remarkable insight because it unified many individual phenomena and observations into a conceptual picture of Earth’s history. With the further assumption that these geologic processes were generally no more or less vigorous than they are today, Hutton's examination of sedimentary layers led him to realize that Earth's history must be enormous, that geologic time is anabyss and human history a speck by comparison.④After Hutton, geologists tried to determine rates of sedimentation so as to estimate the age of Earth from the total length of the sedimentary or stratigraphic record. Typical numbers produced at the turn of the twentieth century were 100 million to 400 million years. These underestimated the actual age by factors of 10 to 50 because much of the sedimentary record is missing in various locations and because there is a long rock sequence that is older than half a billion years that is far less well defined in terms of fossils and less well preserved.⑤Various other techniques to estimate Earth's age fell short, and particularly noteworthy in this regard were flawed determinations of the Sun's age. It had been recognized by the German philosopher Immanuel Kant (1724-1804) that chemical reactions could not supply the tremendous amount of energy flowing from the Sun for more than about a millennium. Two physicists during the nineteenth century both came up with ages for the Sun based on the Sun's energy coming from gravitational contraction. Under the force of gravity, the compressionresulting from a collapse of the object must release energy. Ages for Earth were derived that were in the tens of millions of years, much less than the geologic estimates of the lime.⑥It was the discovery of radioactivity at the end of the nineteenth century that opened the door to determining both the Sun’s energy source and the age of Earth. From the initial work came a suite of discoveries leading to radio isotopic dating, which quickly led to the realization that Earth must be billions of years old, and to the discovery of nuclear fusion as an energy source capable of sustaining the Sun's luminosity for that amount of time. By the 1960s, both analysis of meteorites and refinements of solar evolution models converged on an age for the solar system, and hence for Earth, of 4.5 billion years.译文地球的年龄①希腊历史学家希罗多德是最早有记录的推测地球年龄的观察家之一，他生活在大约公元前480年到公元前425年。
托福TPO36阅读Passage2原文文本+题目+答案解析
为了帮助大家高效备考托福，为大家带来托福TPO36阅读Passage2原文文本+题目+答案解析，希望对大家备考有所帮助。
The origin of Earth’s atmosphere In order to understand the origin of Earth's atmosphere,we must go back to the earliest days of the solar system,before the planets themselves were formed from a disk of rocky material spinning around the young Sun.This material gradually coalesced into lumps called planetesimals as gravity and chance smashed smaller pieces together,a chaotic and violent process that became more so as planetesimals grew in size and gravitational pull.Within each orbit,collisions between planetesimals generated immense heat and energy.How violent these processes were is suggested by the odd tilt and spin of many of the planets,which indicate that each of the planets was,like a billiard ball,struck at some stage by another large body of some kind.Visual evidence of these processes can be seen by looking at the Moon.Because the Moon has no atmosphere,its surface is not subject to erosion,so it retains the marks of its early history.Its face is deeply scarred by millions of meteoric impacts,as you can see on a clear night with a pair of binoculars.The early Earth did not have much of an atmosphere.Before it grew to full size,its gravitational pull was insufficient to prevent gases from drifting off into space,while the solar wind(the great stream of atomic particles emitted from the Sun)had already driven away much of the gaseous material from the inner orbits of the solar system.So we must imagine the early Earth as a mixture of rocky materials,metals,and trapped gases,subject to constant bombardment by smaller planetesimals and without much of an atmosphere. As it began to reach full size,Earth heated up,partly because of collisions with other planetesimals and partly because of increasing internal pressures as it grew in size.In addition,the early Earth contained abundant radioactive materials,also a source of heat.As Earth heated up,its interior melted.Within the molten interior,under the influence of gravity,different elements were sorted out by density.By about 40 million years after the formation of the solar system,most of the heavier metallic elements in the early Earth,such as iron and nickel,had sunk through the hot sludge to the center giving Earth a core dominated by iron.This metallic core gives Earth its characteristic magnetic field,which has played an extremely important role in the history of our planet. As heavy materials headed for the center of Earth,lighter silicates(such as the mineral quartz)drifted upward.The denser silicates formed Earth's mantle,a region almost 3,000 kilometers thick between the core and the crust.With the help of bombardment by comets,whose many impacts scarred and heated Earth's surface,the lightest silicates rose to Earth's surface,where they cooled more rapidly than the better-insulated materials in Earth's interior.These lighter materials,such as the rocks we call granites,formed a layer of continental crust about 35 kilometersthick.Relative to Earth as a whole,this is as thin as an eggshell.Seafloor crust is even thinner,at about 7 kilometers;thus,even continental crust reaches only about 1/200th of the way to Earth's core.Much of the early continental crust has remained on Earth's surface to the present day. The lightest materials of all,including gases such as hydrogen and helium,bubbled through Earth's interior to the surface.So we can imagine the surface of the early Earth as a massive volcanic field.And we can judge pretty well what gases bubbled up to that surface by analyzing the mixture of gases emitted by volcanoes.These include hydrogen,helium,methane,water vapor,nitrogen,ammonia,and hydrogen sulfide.Other materials,including large amounts of water vapor,were brought in by cometary bombardments.Much of the hydrogen and helium escaped;but once Earth was fully formed,it was large enough for its gravitational field to hold most of the remaining gases,and these formed Earth's first stable atmosphere. Paragraph 1:In order to understand the origin of Earth's atmosphere,we must go back to the earliest days of the solar system,before the planets themselves were formed from a disk of rocky material spinning around the young Sun.This material gradually coalesced into lumps called planetesimals as gravity and chance smashed smaller pieces together,a chaotic and violent process that became more so as planetesimals grew in size and gravitational pull.Within each orbit,collisions between planetesimals generated immense heat and energy.How violent these processes were is suggested by the odd tilt and spin of many of the planets,which indicate that each of the planets was,like a billiard ball,struck at some stage by another large body of some kind.Visual evidence of these processes can be seen by looking at the Moon.Because the Moon has no atmosphere,its surface is not subject to erosion,so it retains the marks of its early history.Its face is deeply scarred by millions of meteoric impacts,as you can see on a clear night with a pair of binoculars.The early Earth did not have much of an atmosphere.Before it grew to full size,its gravitational pull was insufficient to prevent gases from drifting off into space,while the solar wind(the great stream of atomic particles emitted from the Sun)had already driven away much of the gaseous material from the inner orbits of the solar system.So we must imagine the early Earth as a mixture of rocky materials,metals,and trapped gases,subject to constant bombardment by smaller planetesimals and without much of an atmosphere. 1.According to paragraph 1,why was the HMS Beacon in the Aegean Sea? A.To capture creatures along the sea bottom. B.To provide Forbes with transportation back and forth across the Aegean. C.To test the effectiveness of a new type of dredge.。
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为了帮助大家高效备考托福，为大家带来托福TPO35阅读Passage2原文文本+题目+答案解析，希望对大家备考有所帮助。
Population Growth in Nineteenth-Century Europe [1]Because of industrialization,but also because of a vast increase in agricultural output without which industrialization would have been impossible,Western Europeans by the latter half of the nineteenth century enjoyed higher standards of living and longer,healthier lives than most of the world's peoples.In Europe as a whole,the population rose from188 million in 1800 to 400 million in1900.By 1900,virtually every area of Europe had contributed to the tremendous surge of population,but each major region was at a different stage of demographic change. [2]Improvements in the food supply continued trends that had started in the late seventeenth century.New lands were put under cultivation,while the use of crops of American origin,particularly the potato,continued to expand.Setbacks did occur.Regional agricultural failures were the most common cause of economic recessions until 1850,and they could lead to localized famine as well.A major potato blight(disease)in1846-1847 led to the deaths of at least one million persons in Ireland and the emigration of another million,and Ireland never recovered the population levels the potato had sustained to that point.Bad grain harvests at the same time led to increased hardship throughout much of Europe. [3]After 1850,however,the expansion of foods more regularly kept pace with population growth,though the poorer classes remained malnourished.Two developments were crucial.First,the application of science and new technology to agriculture increased.Led by German universities,increasing research was devoted to improving seeds,developing chemical fertilizers,and advancing livestock.After 1861,with the development of land-grant universities in the United States that had huge agricultural programs,American crop-production research added to this mix.Mechanization included the use of horse-drawn harvesters and seed drills,many developed initially in the United States.It also included mechanical cream separators and other food-processing devices that improved supply. [4]The second development involved industrially based transportation.With trains and steam shipping,it became possible to move foods to needy regions within Western Europe quickly.Famine(as opposed to malnutrition)became a thing of the past.Many Western European countries,headed by Britain,began also to import increasing amounts of food,not only from Eastern Europe,a traditional source,but also from the Americas,Australia,and New Zealand.Steam shipping,which improved speed and capacity,as well as new procedures for canning and refrigerating foods(particularly after 1870),was fundamental to these developments. [5]Europe's population growth included one additional innovation by the nineteenth century:it combined with rapid urbanization.More and more Western Europeans moved from countryside to city,and big cities grew most rapidly of all.By1850,over half of all the people in England lived in cities,a first in human history.In one sense,this pattern seems inevitable:growing numbers of people pressed available resources on the land,even when farmwork was combined with a bit of manufacturing,so people crowded into cities seeking work or other resources.Traditionally,however,death rates in cities surpassed those in the countryside by a large margin;cities had maintained population only through steady in-migration.Thus rapid urbanization should have reduced overall population growth,but by the middle of the nineteenth century this was no longer the case.Urban death rates remained high,particularly in the lower-class slums,but they began to decline rapidly. [6]The greater reliability of food supplies was a factor in the decline of urban death rates.Even more important were the gains in urban sanitation,as well as measures such as inspection of housing.■Reformers,including enlightened doctors,began to study the causes of high death rates and to urge remediation.■Even before the discovery of germs,beliefs that disease spread by“miasmas”(noxious forms of bad air)prompted attention to sewers and open garbage;■Edwin Chadwick led an exemplary urban crusade for underground sewers in England in the1830s.■Gradually,public health provisions began to cut into customary urban mortality rates.By 1900,in some parts of Western,Europe life expectancy in the cities began to surpass that of the rural areas.Industrial societies had figured out ways to combine large and growing cities with population growth,a development that would soon spread to other parts of the world. Paragraph 1 Q15 The phrase kept pace with in the passage is closest in meaning to A.exceeded B.matched the increase in C.increased the rate of D.caused 正确答案:B 解析：回到原文“After 1850,however,the expansion of foods more regularly kept pace with population growth,though the poorer classes remained malnourished”，这句话主句和从句是转折的关系，从句中的意思是“穷苦阶级在营养方面仍然跟不上”，所以转折之。