Moving water was one of the earliest energy sources to beharnessedto reduce the workload of people and animals. No one knows exactly when the waterwheel was invented, butirrigationsystems existed atleast5,000 years ago, and it seems probable that the earliest waterpowerdevicewas the noria, a waterwheel that raised water forirrigationin attached jars. Thedeviceappears to have evolved no later than the fifthcenturyB.C., perhaps independently in different regions of the Middle and Far East.

The earliest waterpower mills were probably vertical-axis mills for grinding corn, known as Norse or Greek mills, whichseemto have appeared during the first orsecondcenturyB.C. in the Middle East and a few centuries later inScandinavia. In the following centuries, increasinglysophisticatedwaterpower mills were builtthroughoutthe RomanEmpireand beyond its boundaries in the Middle East and northern Europe. In England, the Saxons are thought to have used both horizontal and vertical-axis wheels. The first documented Englishmillwas in the eighthcentury, but three centuries later about 5,000 were recorded, suggesting that everysettlementof any size had itsmill.

Raising water and grinding corn were by no means the only uses of the waterpowermill, and during the following centuries, theapplicationof waterpower kept pace with the developing technologies ofmining, iron working, paper making, and the wool and cotton industries. Water was the mainsourceofmechanicalpower, and by the end of the seventeenthcentury, England alone is thought to have had some 20,000 workingmill. There was muchdebateon therelativeefficiencies of different types of waterwheels. The period from about 1650 until 1800 saw some excellentscientificandtechnicalinvestigations of different designs. They revealedoutputpowers ranging from about 1 horsepower to perhaps 60 for the largest wheels and confirmed that formaximumefficiency, the water should passacrossthe blades assmoothlyas possible and fall away withminimumspeed, havinggivenup almost all of itskineticenergy. (They also proved that, inprinciple, the overshot wheel, a type of wheel in which an overheadstreamof water powers the wheel, should win theefficiencycompetition.)

But then steam power entered thescene, putting the whole future of waterpower indoubt. An energyanalystwriting in the year 1800 would have painted a verypessimisticpicture of the future for waterpower. The coal-fired steamenginewas taking over, and the waterwheel was fast becomingobsolete. However, like many later experts, this one would have suffered from an inability to see into the future. Acenturylater the picture was completely different: by then, the world had an electricindustry, and a quarter of its generatingcapacitywas water powered.

The growth of the electric-powerindustrywas the result of aremarkableseriesofscientificdiscoveries anddevelopmentin electrotechnology during the nineteenthcentury, butsignificantchanges in what we might now call hydro (water) technology also played their part. In 1832, the year of Michael Faraday’s discovery that a changingmagneticfieldproduces an electricfield, a young French engineer patented a new and moreefficientwaterwheel. His name was Benoit Fourneyron, and hisdevicewas the first successful waterturbine. The waterwheel, unaltered for nearly 2,000 years, had finally been superseded.

Half acenturyofdevelopmentwas needed before Faraday’s discoveries inelectricitywere translated into full-scale power stations. In 1881 the Godalming powerstationin Surrey, England, on the banks of the Wey River, created the world’s first publicelectricitysupply. The powersourceof this most modern technology was atraditionalwaterwheel. Unfortunatelythis early plant experienced the problemcommonto many forms of renewable energy: the flow in the Wey River was unreliable, and the waterwheel was soon replaced by a steamengine.

From thisprimitivestart, the electricindustrygrew during the final 20 years of the nineteenthcenturyat arateseldom if ever exceeded by any technology. Thecapacityofindividualpower stations, many of them hydro plants, rose from a few kilowatts to over a megawatt in less than adecade.

Questions:
question_stem: The word “harnessed” in the passage is closest in meaning to
choices: tag: A
text: known

tag: B
text: depended on

tag: C
text: recognized

tag: D
text: utilized
answer_key: D
explanation: D  harness: 利用，治理。对应 D 选项的 utilize（利用，运用）。对应原文 Moving water was one of the earliest energy sources to be harnessed to reduce the workload of people and animals.这个单词后面出现了 to，表目的或作用，整句话的意思就是水资源被用于减轻人和动物的劳动。所以很容易推出文中单词 harneesed 是使用的意思。因此选择 D。

question_stem: In paragraph 1, uncertainty is expressed about all of the following aspects of the early development of waterpower EXCEPT
choices: tag: A
text: when exactly the very first waterpower devices were invented

tag: B
text: when exactly the very first waterpower devices were developed

tag: C
text: whether water was one of the earliest sources of power to be used by humans

tag: D
text: whether the very earliest waterpower devices arose independently
answer_key: C
explanation: A 选项用 first waterpower devices 定位到原文第二句： No one knows exactly when the waterwheel was invented...这句话说了 no one knows,正确，不选。B 选项中的 when 和最后一句话的地点呼应： The device appears to have evolved no later than the fifth century B.C., perhaps independently in different regions of the Middle and Far East. B 正确，不选。C 的 earlist 定为到第一句话： Moving water was one of the earliest energy sourcesMoving water was one of the earliest energy sources.说明这个事实是肯定的。C 是要选的答案 D 选项用 arose independently 对应这段的最后一句：...perhaps independently in different regions of the Middle and Far East.其中 perhaps 说明这个事情并不肯定。所以 D 不选。

question_stem: According to paragraph 2, what was true of the waterpower mills built throughout the Roman Empire?
choices: tag: A
text: Most had horizontal-axis wheels

tag: B
text: Their design was based on mills that had long been used in Scandinavia

tag: C
text: Their design was more popular beyond the Empire’s boundaries than it was within the Empire.

tag: D
text: They are more advanced than the mills used in the Middle East at an earlier time.
answer_key: D
explanation: 对应题目找到原文对应句： increasingly sophisticated waterpower mills were built throughout the Roman Empire 因而选择 D 项：they are more advanced than the mills used in the Middle East at an earlier time.

question_stem: The phrase "the application of waterpower" in the passage is closest in meaning to
choices: tag: A
text: the uses to which waterpower was put

tag: B
text: the improvement made to waterpower

tag: C
text: the method by which waterpower was supplied

tag: D
text: the source of waterpower available
answer_key: A
explanation: A application: 应用。这里的 application 指的是水力资源的应用，也就是作用。因此选择 A，水利的用处。对应原文 Raising water and grinding corn were by no means the only uses of the waterpower mill, and during the following centuries, the applications of waterpower kept pace with the developing technologies of mining, iron working, paper making, and the wool and cotton industries.从语境中去看，前半句话就说提水和磨谷物不是唯一使用水利的方面，而下半句话必定强调还有其他的应用，这样就很好推测了。A 最为合适。

question_stem: According to paragraph 3, which of the following was discovered as a result of scientific and technical investigations of waterpower conducted between 1650 and 1800?
choices: tag: A
text: Some types of small waterwheel can produce as much horsepower as the very largest wheels.

tag: B
text: Waterwheels operate more efficiently when water falls away from their blades slowly than when water falls away quickly.

tag: C
text: Waterwheel efficiency can be improved by increasing the amount of kinetic energy water contains as it passes over a waterwheel’s blades.

tag: D
text: Unlike other types of waterwheels, the overshot wheel is capable of producing more than 60 horsepower units of energy.
answer_key: B
explanation: B 通过 scientific and technical investigation 定位到第一句，后面几句就是调查的结果了，原文说输出的功率从1-60 马力不等，水流越 smooth，下落越慢，效率就越高。因此，A 选项，原文没提到。B 选项正确。C. water contain 的动能并不能改变，而是要尽可能的使其含有的动能释放出来。D 提到了 overshot wheel，对应本段最后一句。但是原文并没说这种轮就能输出高于60 马单位的能量。

question_stem: The word “pessimistic” in the passage is closest in meaning to
choices: tag: A
text: negative

tag: B
text: unlikely

tag: C
text: surprising

tag: D
text: incomplete
answer_key: A
explanation: A pessimistic: 悲观的。是 optimistic 的反义词。对应 A 选项的 negative（负面的，消极的）。对应原文 An energy analyst writing in the year 1800 would have painted a very pessimistic picture of the future for waterpower.根据前面一句，有了蒸汽动力以后，水力资源就被 put in doubt 了。因此后面修饰水力资源利用前景的一定是一个负面的词。因此选择 A，负面的。B 是不相似的，C 是令人吃惊的，D 是不完整。

question_stem: The term “by then” in the passage refers to
choices: tag: A
text: by the time steam power entered the scene

tag: B
text: by the year 1800

tag: C
text: by the year 1900

tag: D
text: by the time waterwheel was becoming obsolete
answer_key: C
explanation: C 因为前文提到在1800 年，水力资源利用衰败，by then 的前半句说 a century later，因此应该是一百年以后，也就是1900 年。

question_stem: According to paragraph 4, why did waterpower become more importantly by 1900?
choices: tag: A
text: Better waterwheel designs improved the efficiency of waterpower.

tag: B
text: Waterpower was needed to operate steam engines.

tag: C
text: Waterpower was used to generate electricity.

tag: D
text: Waterwheels became more efficient than coal-powered engines.
answer_key: C
explanation: C 这一段前半段在说蒸汽取代了水利，水利处于不利地位，但是，从 However 这里开始转折，后面就说水利能源的重大改变促进了电力发展。因此符合 C 选项。其他三个选项在原文中都没有提及。

question_stem: Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.
choices: tag: A
text: The growth of the electric-power industry stimulated significant changes in hydro technology and scientific progress in electrotechnology in the nineteenth century.

tag: B
text: The changes in hydro technology that led to the growth of the electric-power industry also led to discoveries and developments in electrotechnology in the nineteenth century.

tag: C
text: Advances in electrotechnology in the nineteenth century and changes in hydro technology were responsible for the growth of the electric-power industry.

tag: D
text: In the nineteenth century, the scientific study of electrotechnology and hydro technology benefited greatly from the growth of the electric-power industry.
answer_key: C
explanation: C 原文句子的逻辑关系是，electrotechnology 和 changes in water growth 共同促进了 electric power 工业。A 逻辑关系完全反了。B 混乱的。D 与 A 逻辑相似。因此选择 C。

question_stem: The word “unaltered” in the passage is closest in meaning to
choices: tag: A
text: unimproved

tag: B
text: unequaled

tag: C
text: unchanged

tag: D
text: unsatisfactory
answer_key: C
explanation: C unaltered: 一成不变的。对应 C 选项的 unchanged。对应原文 The waterwheel, unaltered for nearly 2,000 years, had finally been superseded.可以通过上下文来判断，前文在说 Benoit 发明了 water tubine,而这句话说了 waterwheel 被(superseded)取代了,这样来推测 unaltered 在这里和哪个选项更接近。A 为迷惑选项，最容易错选，但是一成不变和没有进步之间还是有意思上的差距的。

question_stem: The discussion of the history of electric power production in paragraph 5 supports which of the following?
choices: tag: A
text: 1832 marked the beginning of the industrial production of electric power.

tag: B
text: Turbines using Benoit Fourneyron’s design were eventually used to generate electric power.

tag: C
text: Benoit Fourneyron quickly applied Michael Faraday’s discovery about electric fields to acquire a patent for a new and more efficient waterwheel.

tag: D
text: Practical advances in hydro technology were more important to the development of electric power than were advances in the theoretical understanding of electricity.
answer_key: B
explanation: B 没有特别好的定位词，需要通读理解。文中刚说了 hydro technology 也对电力工业起到了作用，接着就说了 benoit 发明了 water turbine。这个 hydro technology 对于电力工业起到作用，也就是可以用来发电。对应 B 选项。A 选项原文无提及；C 选项和原文矛盾，没说 Benoit 去获取 patent;D 选项的 more imporant 在原文无体现。

question_stem: According to paragraph 6, what problem did the early power station in the town of Godalming in Surrey, United Kingdom, face in providing electricity?
choices: tag: A
text: The traditional waterwheel is used was not large enough to meet the demand for energy.

tag: B
text: The flow of the River Wey, on which the power station depended, was unreliable.

tag: C
text: The operators of the Godalming power station had little experience with hydro technology.

tag: D
text: The steam engine that turned the waterwheel was faulty and needed to be replaced.
answer_key: B
explanation: B 通过 Godalming 定位。往后阅读之后出现了 unfortunately 的转折，也就是要说遇到的问题了: Unfortunately this early plant experienced the problem common to many forms of renewable energy: the flow in the Wey River was unreliable, and the waterwheel was soon replaced by a steam engine.说了水流不是很稳定，unreliable。所以选 B。