托福閱讀tpo 1 Groundwater 地下水原題解析

1、閱讀原文：?Groundwater is the word used to describe water that saturates the ground, filling all the available spaces. By far the most abundant type of groundwater is meteoric water; this is the groundwater that circulates as part of the water cycle. Ordinary meteoric water is water that has soaked into

2、the ground from the surface, from precipitation (rain and snow) and from lakes and streams. There it remains, sometimes for long periods, before emerging at the surface again. At first thought it seems incredible that there can be enough space in the solid ground underfoot to hold all this water.地下水

3、是指滲入到地下并將所有巖石孔隙填滿的水。到現(xiàn)在為止，大氣水是最豐富的地下水資源，是地下水在水循環(huán)中的一個(gè)環(huán)節(jié)。普通的大氣水會(huì)從地表、降水以 及湖泊河流侵入到地下。在再次冒出地表之前，這些地下水有時(shí)會(huì)長時(shí)間留在地下。最初讓人覺得難以置信的是，在我們腳下“堅(jiān)實(shí)的”土地中竟然有足夠的空間能 儲(chǔ)存這么些水。The necessary space is there, however, in many forms. The commonest spaces are those among the particlessand grains and tiny pebblesof loose, unconsol

4、idated sand and gravel. Beds of this material, out of sight beneath the soil, are common. They are found wherever fast rivers carrying loads of coarse sediment once flowed. For example, as the great ice sheets that covered North America during the last ice age steadily melted away, huge volumes of w

5、ater flowed from them. The water was always laden with pebbles, gravel, and sand, known as glacial outwash, that was deposited as the flow slowed down.然而，地下水所需的儲(chǔ)存空間多種多樣。松散的砂子和礫石間有許多顆粒，如沙粒和小石子，它們之間的孔隙是最常見的儲(chǔ)存地下 水的空間。由這些顆粒組成的水床非常普遍，通常位于看不見的土壤下方，在攜帶粗糙沉淀物的湍急的河流曾流過的地方都能找到它們的蹤跡。比如，冰河時(shí)代覆蓋 北美的巨大冰層逐漸融化，大量水從那兒

6、流出。水里總會(huì)攜帶些石子、礫石和沙石，這些顆粒會(huì)隨著水流的減速而沉淀，這就是所謂冰河期的冰水沉積。The same thing happens to this day, though on a smaller scale, wherever a sediment-laden river or stream emerges from a mountain valley onto relatively flat land, dropping its load as the current slows: the water usually spreads out fanwise, depositin

7、g the sediment in the form of a smooth, fan-shaped slope. Sediments are also dropped where a river slows on entering a lake or the sea, the deposited sediments are on a lake floor or the seafloor at first, but will be located inland at some future date, when the sea level falls or the land rises; su

8、ch beds are sometimes thousands of meters thick.現(xiàn)代也有冰水沉積，盡管規(guī)模相對(duì)較小。凡是有攜帶沙石的河流或者溪流從山谷流至相對(duì)平坦的地面時(shí)，砂石就隨著水流速度的減慢逐漸沉淀；水流通常呈扇形擴(kuò)散， 它們所攜帶的沙石也會(huì)沉淀為光滑的扇形斜面。當(dāng)河流匯入湖泊和海洋的時(shí)候也會(huì)有沉淀，這些沉淀最初在湖底或海底，但將來海平面下降或者陸地崛起時(shí)，它們就 會(huì)分布于內(nèi)陸，通常厚達(dá)幾千米。In lowland country almost any spot on the ground may overlie what was once the bed of a ri

9、ver that has since become buried by soil; if they are now below the waters upper surface (the water table), the gravels and sands of the former riverbed, and its sandbars, will be saturated with groundwater.低地區(qū)域上的任何位置可能就是曾經(jīng)的河床，后續(xù)被土壤覆蓋而變成現(xiàn)在的樣子。如果那些過去的河床和沙洲現(xiàn)在位于地下水位之下，一定會(huì)有大量的地下水浸在它們的沙子和礫石之間。So much for

10、 unconsolidated sediments. Consolidated (or cemented) sediments, too, contain millions of minute water-holding pores. This is because the gaps among the original grains are often not totally plugged with cementing chemicals; also, parts of the original grains may become dissolved by percolating grou

11、ndwater, either while consolidation is taking place or at any time afterwards. The result is that sandstone, for example, can be as porous as the loose sand from which it was formed.以上說的都是松散的沉積物，那些堅(jiān)固的沉積物，也擁有以數(shù)萬計(jì)的毛細(xì)孔來容納水。因?yàn)樽畛躅w粒間的縫隙通常并未完全被黏固的化學(xué)物質(zhì)塞滿，而且部分顆粒很可能在固化時(shí)或固化后被滲入的地下水溶解；結(jié)果這些砂巖最終變得和形成它的散沙一樣多孔。Thus

12、 a proportion of the total volume of any sediment, loose or cemented, consists of empty space. Most crystalline rocks are much more solid; a common exception is basalt, a form of solidified volcanic lava, which is sometimes full of tiny bubbles that make it very porous.因此，不管沉積物是疏松還是堅(jiān)固，它們中一定有空間。大部分結(jié)晶

13、體巖石都非常堅(jiān)硬，但也有例外，最常見的就是玄武巖，它是一種固化的火山熔巖，經(jīng)常充滿了微小氣泡，從而變得十分多孔。The proportion of empty space in a rock is known as its porosity. But note that porosity is not the same as permeability, which measures the ease with which water can flow through a material; this depends on the sizes of the individual cavities

14、 and the crevices linking them.巖石的孔隙度就是指其中空間的比例。但需要注意的是，孔隙度與滲透率是不同的。滲透率衡量的是水滲透物質(zhì)的難易程度，它取決于與單個(gè)空隙以及連接孔隙間裂縫的大小。Much of the water in a sample of water-saturated sediment or rock will drain from it if the sample is put in a suitable dry place. But some will remain, clinging to all solid surfaces. It is h

15、eld there by the force of surface tension without which water would drain instantly from any wet surface, leaving it totally dry. The total volume of water in the saturated sample must therefore be thought of as consisting of water that can, and water that cannot, drain away.當(dāng)充滿水分的沉淀物或者巖石樣本被放置在適宜的干燥

16、環(huán)境中時(shí)，大部分的水分會(huì)流失，但仍有部分水會(huì)繼續(xù)附著在堅(jiān)實(shí)的表面上。要不是因?yàn)楸砻鎻埩Γ@些水分也會(huì)立刻蒸發(fā)，僅留下完全干燥的樣本。因此，試驗(yàn)樣本的含水量既包括可以流干的水，也包括不能流干的水。The relative amount of these two kinds of water varies greatly from one kind of rock or sediment to another, even though their porosities may be the same. What happens depends on pore size. If the pores

17、are large, the water in them will exist as drops too heavy for surface tension to hold, and it will drain away; but if the pores are small enough, the water in them will exist as thin films, too light to overcome the force of surface tension holding them in place; then the water will be firmly held.

18、這兩種水的相對(duì)含量因巖石或沉積物種類不同而改變，即便它們有相同比例的孔隙，還取決于孔隙的大小。如果孔隙很大，其中的水會(huì)形成水滴，太重足以克服吸引它的表面張力，就會(huì)流走；但如果孔隙夠小，水會(huì)像薄膜一樣，太輕無法克服表面張力，從而穩(wěn)穩(wěn)地附著在孔隙表面上。第1題：Which of the following can be inferred from paragraph 1 about the ground that we walk on?A：It cannot hold rainwater for long periods of time.B：It prevents most groundwater

19、 from circulating.C：It has the capacity to store large amounts of water.D：It absorbs most of the water it contains from rivers.解析：以下哪一項(xiàng)能夠從第一段推出與我們走的路地有關(guān)？（Inference Question）a)它不能長時(shí)間儲(chǔ)存水。b)它阻止了大部分地下水進(jìn)行水循環(huán)。c)它有能力儲(chǔ)存大量的地下水。d)它大部分的水從河流中吸收。根據(jù)“ground that we walk on”定位到段落最后一句話“At first thought it seemsincre

20、diblethatthere can be enough spacein the “solid” ground underfootto hold all this water.”意思是：一開始很難想象我們腳下的地有足夠的空間容下這些水。選項(xiàng)一錯(cuò)，倒數(shù)第二句“There it remains, sometimesfor long periods, before emerging at the surface again.”For long periods長時(shí)間；remain v.保持；emerge v.出現(xiàn)；選項(xiàng)二錯(cuò)，段落第二句“By far themostabundanttype of gro

21、undwater is meteoric water; this is the groundwater that circulates as part of thewater cycle.”意思是：現(xiàn)在最豐富的地下水類型是雨水；這些雨水是進(jìn)入水循環(huán)的那部分；by far最；abundant adj.富足；circulate v.循環(huán)；選項(xiàng)四錯(cuò)，段落第三句“Ordinary meteoric water is water that has soaked into the groundfrom the surface,fromprecipitationandfrom lakes and strea

22、ms.”意思是：平常的雨水都是那些從地表、降水和河流湖泊中滲入地下的水。soak v.滲透；precipitationn.降雨，降雪；第2題：The word incredible in the passage is closest in meaning toA：confusingB：comfortingC：unbelievableD：interesting解析：與單詞incredible在文章中意思最接近的是（Vocabulary Question）a)Confusing（令人迷惑的）b)Comforting（安慰人的）c)Unbelievable（難以置信的）d)Interesting（有

23、趣的）查字典! Incredible adj.難以置信的；in-否定前綴；cred詞根，意思“信用”；-ible形容詞后綴；un-否定前綴；believe v.相信；-able形容詞后綴；incredible和unbelievable也是?？纪x詞對(duì)子。第3題：The word out of sight in the passage is closest in meaning toA：far awayB：hiddenC：partly visibleD：discovered解析：與單詞“out of sight”在文中意思最接近的是（Vocabulary Question）a)Far away（

24、遙遠(yuǎn)）b)Hidden（隱藏）c)Partly visible （部分可見）d)Discovered（發(fā)現(xiàn)的）sight n.眼界；out of sight眼界之外；有一個(gè)俗語：Out of sight, out of mind;眼不見心不煩；隱藏的肯定看不見；far away遙遠(yuǎn)也可以看得見，比如夜晚空中的星星；第4題：According to paragraph 2, where is groundwater usually found?A：Inside pieces of sand and gravelB：On top of beds of rockC：In fast rivers th

25、at are flowing beneath the soilD：In spaces between pieces of sediment解析：根據(jù)第二段，通常在哪里能找到地下水？（Factual Information Question）a)在沙子和沙礫碎片中b)在巖石床的上面c)在泥土下快速流動(dòng)的河水中d)在沉積物碎片之間的空隙根據(jù)段落前兩句話“The necessary space is there, however, in many forms. The commonest spaces arethose among the particles-sand grains and tiny

26、 pebbles-of loose, unconsolidated sand and gravel.”意思是：必須的空間就在那兒，盡管形式多樣。最平常的空間是那些松散不堅(jiān)固的沙子和沙礫微粒（礫子和小石子）間的空隙。Particle n.粒子；grain n.粒子；pebble n.小鵝卵石；gravel n.沙礫；loose adj.松的；consolidate adj.堅(jiān)固的；unconsolidated adj.不堅(jiān)固的；選項(xiàng)一錯(cuò)，不是在sand和gravel里面，而是在它們的縫隙里面；those among the particles；those代表的是space；選項(xiàng)二和三也都錯(cuò)在不是

27、空隙；只有選項(xiàng)四有spaces，并且段落第四句“They are found wherever fast rivers carryingloads of coarse sedimentonce flowed.”第5題：The phrase glacial outwash in the passage refers toA：fast riversB：glaciersC：the huge volumes of water created by glacial meltingD：the particles carried in water from melting glaciers解析：用語glac

28、ial outwash在文中指（Reference Question）a)快速河流b)冰川c)冰川融化形成大量的水d)冰川融化的水中帶的微?；氐皆洹癟he water was always laden with pebbles, gravel,andsand,known as glacial outwash, that was deposited as the flow slowed down.”意思是：水?dāng)y帶卵石、沙礫和沙子，這些被稱為glacial outwash，水流緩慢時(shí)沉積下來。根據(jù)Known as用語的意思就能判斷出glacial outwash指的是pebbles, grave

29、l, and sand而這三樣?xùn)|西都由水?dāng)y帶，水又是冰川融化而得，所以答案選第四項(xiàng)；Known as被稱之為;be laden with裝滿。；deposit v.沉淀；slow down慢下來；第6題：All of the following are mentioned in paragraph 3 as places that sediment-laden rivers can deposit their sediments EXCEPTA：A mountain valleyB：Flat landC：A lake floorD：The seafloor解析：以下地點(diǎn)在第三段中都提到作為河流

30、沉積沉積物的地方，除了（Negative Factual Information Question）a)山谷中b)平地c)湖底d)海底段落第一句“The same thing happens to.emerges from a mountain valley onto relatively flat land,dropping its loadas the current slows”所以平地是有的；再看第二句“Sediments are also dropped where.the deposits sediments areon a lake floor or the seafloor a

31、t first.”因此，湖底和海底也行；山谷是沒有的，文章只說了河流會(huì)從山谷流到平地，沒說過是否在山谷中沉淀。Emerge v.出現(xiàn)；drop v.放下；spread out展開；第7題：The word overlie in the passage is closest in meaning toA：coverB：changeC：separateD：surround解析：與單詞overlie在文章中意思最接近的是（Vocabulary Question）a)Cover（覆蓋）b)Change（改變）c)Separate （分離）d)Surround（包圍）查字典，overlie的意思是“躺在

32、。上面”；毫無疑問cover是組接近的。Overlie和cover都只有在上方的意思。Surround是四面八方，這樣才能稱作包圍，所以不對(duì)。第8題：The phrase So much for in the passage is closest in meaning toA：that is enough aboutB：now let us turn toC：of greater concern areD：this is related to解析：與用語“so much for”在文章中意思最接近的是（Vocabulary Question）a)That is enough about (關(guān)于

33、。已經(jīng)足夠了)b)Now let us turn to（現(xiàn)在，我們換一個(gè)話題到。）c)Of greater concern are(更擔(dān)心的是)d)This is related to（這與。有關(guān)）so much for .關(guān)于已經(jīng)很多了。只有This is enough about是匹配的。經(jīng)常在轉(zhuǎn)換話題的時(shí)候都會(huì)用這兩句話：Thats so much for A./ Thats enough about A.；第9題：The word plugged in the passage is closet in meaning toA：washedB：draggedC：filled upD：so

34、aked through解析：與單詞plugged在文中意思最接近的是（Vocabulary Question）a)Washed（沖刷）b)Dragged（拖，拉）c)Filled up（充滿）d)Soaked through（滲入）plug v.堵，賽，插上；含義與充滿是一樣的。第10題：According to paragraphs 6 and 7, why is basalt unlike most crystalline forms of rock?A：It is unusually solid.B：It often has high porosity.C：It has a low p

35、roportion of empty space.D：It is highly permeable.解析：根據(jù)第六段和第七段，為什么basalt與其它晶體巖石不一樣？（Factual Information Question）a)它不同尋常地堅(jiān)固。b)它通常有高多孔性。c)它的空隙空間比例很低。d)它的浸透性很高?；氐降诹蔚诙洹癕ost crystalline rocks are much more solid; a common exception is basalt, a form of solidified volcanic lava, which is sometimesfull

36、of tiny bubbles that make it very porous.”意思是：大多數(shù)晶體巖石都很堅(jiān)固；有一個(gè)特例是玄武巖，這是一種固化的火山熔巖，它有時(shí)充滿了小的氣泡使得它變得很多空。Solid adj.堅(jiān)固的；solidify v.固化；lava n.熔巖；bubble n.氣泡；porous adj.多孔的；exception n.特例；exceptional adj.異常的第11題：What is the main purpose of paragraph 7?A：To explain why water can flow through rockB：To emphasiz

37、e the large amount of empty space in all rockC：To point out that a rock cannot be both porous and permeableD：To distinguish between two related properties of rock解析：第七段的主要目的是什么？（Rhetorical Purpose Question）a)為了解釋為什么水能夠流過巖石b)為了強(qiáng)調(diào)巖石中大量的空隙空間c)為了指出一塊巖石很難即多孔又能滲透d)區(qū)別兩種相關(guān)的巖石性質(zhì)第七段重要解釋區(qū)分了permeability和porosit

38、y這兩種巖石性質(zhì)。Porosity是孔隙度，即一塊巖石中空隙空間的比例；permeability是滲透性，指的水穿過一種物質(zhì)的難易程度。第12題：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.A：Surface tension is no

39、t strong enough to retain drops of water in rocks with large pores but it strong enough to hold on to thin films of water in rocks with small pores.B：Water in rocks is held in place by large pores and drains away from small size pores through surface tension.C：Small pores and large pores both intera

40、ct with surface tension to determine whether a rock will hold water as heavy drops or as a thin film.D：If the force of surface tension is too weak to hold water in place as heavy drops, the water will continue to be held firmly in place as a thin film when large pores exist.解析：以下哪一項(xiàng)能表達(dá)出高亮句子的精華核心含義？錯(cuò)

41、誤選項(xiàng)改變重要含義或者遺漏精華信息。（Sentence Simplification Question）If the pores are large, the water in them will exist as drops too heavy for surface tension to hold, and it will drain away; but if the pores are small enough, the water in them will exist as thin films, too light to overcome the force of surface t

42、ension holding them in place; then the water will be firmly held.如果空隙很大，它們中的水會(huì)以小水滴的形式存在，這樣太重了以至于表面拉力不夠，于是水會(huì)流干；但是如果空隙足夠小，它們中的水會(huì)以薄片的形式存在，這樣太輕以至于克服不了表面拉力，于是水就被緊緊地抓住了。句子的主干是：If the pores are large, the water.; If the pores are small enough, the water.;Too to太而不能；hold v.抓??；drain away流干；overcome v.克服；tens

43、ion n.拉力；force n.力量；exist as以。存在；a)表面拉力沒有強(qiáng)到可以留住巖石大空隙中的水滴，但足夠留下小空隙中的薄片。b)巖石中的水通過大孔隙留住，通過表面拉力從小空隙流干。c)小空隙和大孔隙與表面張力相互作用以決定一塊巖石是能留住水滴還是水薄片。d)如果表面張力太弱而抓不住重水滴，水會(huì)接著以薄片的形式被牢牢抓住當(dāng)大孔隙存在時(shí)。第13題：Look at the four squares that indicate where the following sentence could be added to the passage. Where would the sent

44、ence best fit?What, then, determines what proportion of the water stays and what proportion drains away?解析：Look at the four squaresthat indicate where the following sentence could be added to the passage.What, then , determines what proportion of the water stays and what proportion drains away?那，是什么

45、決定哪部分水留下，哪部分水流干？Proportion n.部分；drain away流干看大句子的第一反應(yīng)便是句子之后肯定要有文章內(nèi)容回答這個(gè)問題。發(fā)現(xiàn)只有第九段回答了此問題，所以答案是第四個(gè)插入口。第14題：Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the

46、passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.Much of the ground is actually saturated with water.A. Sediments that hold water were spread by glaciers and are still spread by rivers and streams.B. Water is stored underground in beds of loose sand and gravel or in cemented sediment.C. The size of a saturated rocks pores determines how much water it will retain when the rock is put in a dry place.D. Groundwater often remains undergroun