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1、 为了帮助大家高效备考托福， 为大家带来托福 TPO28 阅读 Passage1 原文文本+题目+答案 解析，希望对大家备考有所帮助。 Groundwater Most of the worlds potable water-freshwater suitable for drinking is accounted for bygroundwater,which is stored in the pores andfractures in rocks.There is more than 50 times asmuch freshwater stored underground than in
2、 all the freshwater rivers and lakes at the surface.Nearly 50 percent of all groundwater is stored in the upper 1,000 meters of Earth.At greaterdepths within Earth,the pressure of the overlying rock causes pores and cracks to close,reducing the space that pore water can occupy,and almost complete cl
3、osure occurs at a depthof about 10 kilometers.The greatest water storage,therefore,lies near the surface. 世界上绝大部分饮用水-可以饮用的淡水-都是地下水，它们储藏在岩石孔隙和裂 缝中。储藏于地下的淡水是地表淡水河流和湖泊中总水量的 50 倍。大约 50%的地下水存在于 地下深 1000m 以内的地层中。随深度增加，上覆岩层压力使岩石孔隙和裂缝闭合，减少了水 的储存空间， 而超过 10 公里深的地下孔隙几乎全部闭合。 因此绝大部分水储存于接近地表的 地层中。 Aquifers,Porosi
4、ty and Permeability 水层，孔隙度和渗透率 【2】Groundwater is stored in a variety of rock types.A groundwater reservoir from whichwater can be extracted is called an aquifer.We can effectively think of an aquifer as a depositof water.Extraction of water depends on two properties of the aquifer:porosity andpermea
5、bility.Between sediment grains are spaces that can be filled with water.This porespace is known as porosity and is expressed as a percentage of the total rock volume.Porosityis important for waterstorage capacity,but for water to flow through rocks,the pore spacesmust be connected.The ability of wat
6、er,or other fluids,to flow through the interconnected porespaces in rocks is termed permeability.In the intergranular spaces of rocks,however,fluidmust flow around and between grains in a tortuous path;this winding path causes aresistance to flow.The rate at which the flowing water overcomes this re
7、sistance is relatedto the permeability of rock. 地层水储存在多种岩石中。可以取出的地下水的聚集层叫做水层。我们可以认为水层即 水的聚集地层。从地层中取水取决于水层的两个因素：孔隙度和渗透率。沉积颗粒之间的空 间可以储存水，这种孔隙空间由孔隙度表征。孔隙度是岩石孔隙体积与总体积的百分比。孔 隙度对地层储水能力尤为重要，但欲使水从岩石中流出，孔隙之间必须相互连通。水或其它 流体从相互连通的孔隙中流动的能力即为渗透率。在粒间孔发育的岩石中，流体必须在颗粒 周围的曲折通道中流动;这种曲折通道会对流动产生阻力。 水克服阻力流动的速率与岩石渗透 率相关。 【
8、3】Sediment sorting and compaction influence permeability and porosity.The more poorlysorted or the more tightly compacted a sediment is,the lower its porosity and permeability.Sedimentary rocksthe most common rock type near the surfaceare also the most commonreservoirs for water because they contain
9、 the most space that can be filled with water.Sandstones generally make good aquifers,while finer-grained mudstones are typicallyimpermeable.Impermeable rocks are referred to as aquicludes.Igneous and metamorphicrocks are more compact,commonly crystalline,and rarely contain spaces between grains.How
10、ever,even igneous and metamorphic rocks may act as groundwater reservoirs if extensivefracturing occurs in such rocks and if the fracture system is interconnected. 沉积物的分选性和压实程度影响其渗透率和孔隙度。岩石分选越差或压实越紧则其孔隙 度和渗透率越低。沉积岩-地表最常见的岩石-也是最常见的水储集层，因为它们常带 有最多的可以储水的孔隙空间。 砂岩一般是最好的储水层， 但小颗粒的泥岩则通常不可渗透。 不渗透岩层都称为隔水层。火成
11、岩和变质岩压实更紧，通常有结晶，并几乎没有粒间孔隙。 但是即便是火成岩和变质岩也可因裂缝大量发育并相互连接而成为储水层。 The Water Table 地下水位 【4】The water table is the underground boundary below which all the cracks and pores arefilled with water.In some cases,the water table reaches Earth s surface,where it is expressedas rivers,lakes and marshes.Typically,
12、though,the water table may be tens or hundreds ofmeters below the surface.The water table is not flat but usually follows the contours of thetopography.Above the water table is the vadose zone,through which rainwater percolates.Water in the vadose zone drains down to the water table,leaving behind a
13、 thin coating of wateron mineral grains.The vadose zone supplies plant roots near the surface with water. 地下水位指地层岩石裂缝和孔隙充满水的边界。某些情况下，地下水位可能到达地表， 在那里它以河流、湖泊或沼泽地的形式存在。但通常情况下地下水位位于地面数十或数百米 以下。地下水位不是水平的，而是通常沿着地势起伏。地下水位以上称为包气带，在这里降 水得以过滤。包气带中的水会沉降到地下水位，只在矿物颗粒表面留下一层水膜。包气带为 地表附近植物根部提供水分。 【5】Because the sur
14、face of the water table is not flat but instead rises and falls withtopography,groundwater is affected by gravity in the same fashion as surface water.Groundwater flows downhill to topographic lows.If the water table intersects the land surface,groundwater will flow out onto the surface at springs,w
15、eather to be collected there or tosubsequently flow farther along a drainage.Groundwater commonly collects in streamdrainages but may remain entirely beneath the surface of dry stream-beds in arid regions.Inparticularly wet years,short stretches of an otherwise dry stream-bed may have flowing waterb
16、ecause the water table rises to intersect the land surface. 因为地下水位表面并非水平，而是沿着地势起伏，地下水和地表水受到重力影响的模式 相同。地下水沿着下倾地层流向地势低洼处。如果地下水位与地表相交，地下水将以喷泉的 形式流出地面，要么就地聚集，要么沿排水通道流向更远的地方。地下水通常在小溪中聚集， 但在干旱地区也可能全部停留在干涸河床下。在特定湿润的年月里，一段干涸的河床下游可 能有水流动，因为地下水位抬升到了那里的地表以上。 Glossary Sediment:materials(such as sand or small ro
17、cks)that are deposited by water,wind,or glacialice. Topography:the shape of a surface such as Earths,including the rise and fall of such featuresas mountains and valleys. 托福阅读试题 1.In paragraph 1,why does the author mention“the pressure of the overlying rock“? A.To show how water can be forced deep u
18、nderEarths surface. B.To show why groundwater is more plentiful than surface freshwater. C.To correct a commonly made error about the location of groundwater. D.To explain why most groundwater lies near Earths surface. 1.在高亮部分的描写之后，本段的最后一句出现了，therefore。这里也是在说 the pressure of the overlying rock 导致的结果
19、，也就是文章提到它的目的。其结果是，大部分 的水储都在比较表面的地方。所以其目的就是要解释为什么水都在表面的地方。 2.According to paragraph 1,groundwater differs from the water in riversand lakes interms of its A.portability. B.usefulness. C.abundance. D.cost. 2.对应原文第二句话，也就是将地下水和江河湖泊水进行比较的那句话。原句说 more than 50 times。就证明是地下水的水量大。这里 A 是饮用性，原文并没有说江水不能喝。B 是有用，
20、同理。D 是代价。这个就更没提到了。所以答案为 C 丰富。 3.The word“extracted“in the passage(paragraph 2)is closest in meaning to A.used. B.poured. C.removed. D.kept out. 3.extract 本身是汲取，取出的意思。从原文后面一句话可以推测，因为后面说储水土 层可以看作是对一笔水存款，所以前面应该是说可以取出。另外这个词的词缀 ex-本身就有 出的意思。那么 A 是使用，B 是泼出，C 是移动，D 是隔离在外。 4.The word“termed“in the passage(p
21、aragraph 2)is closest in meaning to A.considered. B.called. C.limited to. D.caused by. 4.term 作名词是术语，这个很常用。而这里用了其动词否定形式，那么应该是被术语 为，也就是被命名为。那么 A 是认为，B 是叫做，C 是限制于，D 是由于。所以应该选 B。 5.According to paragraph 2,what does porosity determine? A.The rate at which the aquifers water overcomes resistance to flow
22、. B.The amount of water that the aquifer can hold. C.The likelihood that fractures and joints will occur in the aquifer. D.The depth underground at which the aquifer lies. 5.A 决定于 permeability of rack，对应本段最后一句。B 正确，对应本段第七句 (porosity is important for water-storage capacity)， 这句话只要根据 porosity 定位就很 好找。
23、C 和 porosity 没有直接关系。D 原文就没提到。 6.According to paragraph 2,what is the relationship between permeability andporosity? A.The more pores a rock has,the higher its porosity but the lower its permeability. B.Rocks with many internal spaces that are not connected with each other will have highporosity but
24、low permeability. C.If water flows through a rock easily,it has high permeability but low porosity. D.Rocks that have high permeability have high porosity and vice versa. 6.对应本段第一句和第二句，即 sorting 和 compaction 会共同影响 permeability，结 合上一段的最后一句理解，多孔性分为两种情况，一种是孔多但是互相不联通，这时 permeability 不高;另一种是孔多并且互相联通，那么 p
25、orosity 高的同时 permeability 也 会高。因此选择 B。其他几个选项的叙述都不完整。这两者的关系并不是简单的正比例。 7.The word“compacted“in the passage(paragraphy 3)is closest in meaning to A.hard. B.compressed. C.heavy. D.deeply buried. pact 是压缩，紧密的意思。通过后面的 and 的并列内容可以推出其词义，因为 and 后面说 rarely contain space，那就是说中间的空间很小。所以选择 B 压缩的。A 是坚硬， C 是重的，D 是
26、深埋的。 8.According to paragraph 3,when can igneous rock serve as an aquifer? A.When it has many connected fractures. B.When it lies next to metamorphic rock. C.When it lies relatively near the surface. D.When it is crystalline. 8.对应本段文章最后一句“even igneous rocks may act as groundwater“后半句给出的 就是答案，那么它说的是要
27、有 fractures 并且要 interconnected。所以选 A。 9.The word“coating“in the passage(paragraph 4)is closest in meaning to A.stream. B.barrier. C.amount. D.layer. 9.Coating 本来是外衣，和涂层的意思。那么 A 是溪流，B 是障碍物，C 是数量，D 是层。 所以 D 符合。 10.Paragraph 4 implies which of the following about the rootsof plants? A.They prevent wate
28、r from reaching the vadose zone. B.They mark the boundary between the vadose zone and the water table C.They do not typically get their water from the water table. D.They help keep the water table from dropping farther. 10.根据plant roots定位到本段最后一句。说vadose zone给植物根部提供了水。选项A，B， D 都没提到。而只有 C 没有错误，因为 plan
29、t roots 是从 vadose zone 汲取的水份，而不是 water table。所以选 C。 11.Which of the sentences below best expresses the essential information in thehighlighted sentence in the passage paragraph 5?Incorrect choices change themeaning in important ways or leave out essential information. A.Groundwater only flows out of
30、 the ground if the water table intersects the land surface. B.If the land surface and the water table intersect,groundwater can flow underground. C.Groundwater may be drained if springs occur where the water table intersects the landsurface. D.Where the water table meets the land surface,groundwater
31、 flows out through surfacesprings. 11.A 选项缺少了 spring 这个条件;B，C 选项不正确。D 包含了原文所有的主干部分，正 确。 12.Paragraph 5 implies which of the following about the level of the water A.It may rise or fall from year to year,depending on annual rainfall. B.It does not vary in arid regions. C.It rarely intersects the land
32、 surface of most regions. D.It is unrelated to the rate at which groundwater flows. 12.根据这段最后两句对于 wet year 的描写可以得出根据降雨量不同，地下水位是有变 化的。 所以 A 正确。 B 不正确， 原文明显写到在 arid regions 降雨量多时干燥的溪床会有水。 C 也不对，整段都有大篇幅在写和 land surface 的 intersects。D 原文没提到。 13.Look at the four squaresthat indicate where the following s
33、entence could beadded to the passage.Where would the sentence best fit?This is a consequence of theslow rate of movement of the groundwater,which often prevents the water tablefrom attaining a flat(horizontal)level. The water table is the underground boundary below which all the cracksand pores are
34、filledwith water.In some cases,the water table reaches Earths surface,where it is expressed asrivers,lakes and marshes.【A】Typically,though,the water table may be tens or hundreds ofmeters below the surface.【B】The water table is not flat but usually follows the contours ofthe topography.【C】Above the
35、water table is the vadose zone,through which rainwaterpercolates.【D】Water in the vadosezone drains down to the water table,leaving behind athin coating of water onmineral grains.The vadose zone supplies plant roots near the surfacewithwater. 13.要插入的句子说 this is a consequence，那么 this 一定指代什么，根据后半句可以 知道
36、指代的内容应该与地下水位不是平面有关。所以 C 的位置符合，因为前面一句说地下水 位不是平面。 14.Directions:An introductory sentence for a brief summary of the passage isprovided below.Complete the summary by selecting the THREE answer choices thatexpress the most important ideas in the passage.Some sentences do not belong inthe summary because
37、 they express ideas that are not presented in the passage or areminor ideas in the passage.This question is worth 2 points. Most of the worlds potable water is stored as groundwater in the poresand fractures ofunderground rock,much of it at depths of less than 1,000 meters. A.Sedimentary rock may ma
38、ke poor aquifers because of tightly compacted sediment,whichreduces porosity and permeability. B.Porosity is a measure of the empty space within rock while permeability measures thedegree to which water can flow freely through rock. C.In arid regions,the water tables remain at a constant level far b
39、elow the surface,preventingstream-beds from filling up even during wet years. D.Groundwater reservoirs are characterized by the porosity and permeability of the rock inwhich they lie,and these factors vary according to the type of rock. E.The vadose zone is typically dry because water does not stay
40、in it,but instead percolatesdown to aquifers below or drains out through springs and streams. F.Although the water table usually follows the contours of the land surface,its level may varyfrom year to year and may intersect to the surface in places. 14.A 错误，对应文章第三段的第三句有关于 sedimentary rock 的描写。根据原文， sedimentary rock 是很好的 aquifers，B 正确，对应第二段的前四句。C 正确，对应原文第 二段。D 错误，vadose zone 中会留下 thin coating 所以还是会湿润。对应原文第四段。E 错 误，water table 本非 remain at a constant level，根据倒数第二句，地下水位有时会和地 表交叉的。F 正确，对应原文最后一段。 以上是给大家整理的托福 TPO28 阅读 Passage1 原文文本+题目+答案解析， 希望对你有所 帮助!