托福TPO1閱讀文本及題目答案Part1
托福TPO是我們托福閱讀的重要參考資料，為了方便大家備考，下面小編給大家整理了托福TPO1閱讀文本及題目答案Part1，希望大家喜歡。
托福TPO1閱讀文本Part1
TPO1 Groundwater
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 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.
The necessary space is there, however, in many forms. The commonest spaces are those among the particles-sand grains and tiny pebbles-of loose, unconsolidated 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 water 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.
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, depositing 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; such beds are sometimes thousands of meters thick.
In lowland country almost any spot on the ground may overlie what was once the bed of a river that has since become buried by soil; if they are now below the water's upper surface (the water table), the gravels and sands of the former riverbed, and its sandbars, will be saturated with groundwater.
So much for 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 groundwater, 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.
Thus 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.
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 and the crevices linking them.
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 held 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.
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 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.
Paragraph 1: 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 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.
托福TPO1閱讀題目Part1
1. Which of the following can be inferred from paragraph 1 about the ground that we walk on?
○It cannot hold rainwater for long periods of time.
○It prevents most groundwater from circulating.
○It has the capacity to store large amounts of water.
○It absorbs most of the water it contains from rivers.
2. The word "incredible" in the passage is closest in meaning to
○confusing
○comforting
○unbelievable
○interesting
Paragraph 2: The necessary space is there, however, in many forms. The commonest spaces are those among the particles-sand grains and tiny pebbles-of loose, unconsolidated 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 water 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.
3. The word "out of sight" in the passage is closest in meaning to
○far away
○hidden
○partly visible
○discovered
4. According to paragraph 2, where is groundwater usually found?
○Inside pieces of sand and gravel
○On top of beds of rock
○In fast rivers that are flowing beneath the soil
○In spaces between pieces of sediment
5. The phrase "glacial outwash" in the passage refers to
○fast rivers
○glaciers
○the huge volumes of water created by glacial melting
○the particles carried in water from melting glaciers
Paragraph 3: 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, depositing 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; such beds are sometimes thousands of meters thick.
6. All of the following are mentioned in paragraph 3 as places that sediment-laden rivers can deposit their sediments EXCEPT
○A mountain valley
○Flat land
○A lake floor
○The seafloor
Paragraph 4: In lowland country almost any spot on the ground may overlie what was once the bed of a river that has since become buried by soil; if they are now below the water's upper surface (the water table), the gravels and sands of the former riverbed, and its sandbars, will be saturated with groundwater.
7. The word "overlie" in the passage is closest in meaning to
○ cover
○ change
○ separate
○ surround
Paragraph 5: So much for 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 groundwater, 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.
8. The phrase "So much for" in the passage is closest in meaning to
○that is enough about
○now let us turn to
○of greater concern are
○this is related to
9. The word "plugged" in the passage is closet in meaning to○washed
○dragged
○filled up
○soaked through
Paragraph 6: Thus 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.
Paragraph 7: 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 and the crevices linking them.
10. According to paragraphs 6 and 7, why is basalt unlike most crystalline forms of rock?
○It is unusually solid.
○It often has high porosity.
○It has a low proportion of empty space.
○It is highly permeable.
11. What is the main purpose of paragraph 7?
○To explain why water can flow through rock
○To emphasize the large amount of empty space in all rock
○To point out that a rock cannot be both porous and permeable
○To distinguish between two related properties of rock
Paragraph 9: 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 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.
12. 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.
○Surface tension is not 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.
○Water in rocks is held in place by large pores and drains away from small size pores through surface tension.
○Small pores and large pores both interact with surface tension to determine whether a rock will hold water as heavy drops or as a thin film.
○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.
Paragraph 8: 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 held 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.
13. Look at the four squares [] that 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?
Where would the sentence best fit?
14. 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 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.
Answer choices
○Sediments that hold water were spread by glaciers and are still spread by rivers and streams.
○Water is stored underground in beds of loose sand and gravel or in cemented sediment.
○The size of a saturated rock's pores determines how much water it will retain when the rock is put in a dry place.
○Groundwater often remains underground for a long time before it emerges again.
○Like sandstone, basalt is a crystalline rock that is very porous.
○B(yǎng)eds of unconsolidated sediments are typically located at inland sites that were once underwater
托福TPO1閱讀答案Part1
托福TPO1閱讀答案：
1. ○3
2. ○3
3. ○2
4. ○4
5. ○4
6. ○1
7. ○1
8. ○1
9. ○3
10. ○2
11. ○4
12. ○1
13. ○4
14. Sediments that hold water…
Water is stored underground…
The size of a saturated rock's…
參考托福TPO1閱讀翻譯：地下水
地下水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(zhǎng)時(shí)間留在地下。最初讓人覺(jué)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。
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(jiàn)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(jiàn)的土壤下方，在攜帶粗糙沉淀物的湍急的河流曾流過(guò)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。
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(lái)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。
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(guò)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。
以上說(shuō)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(wàn)計(jì)的毛細(xì)孔來(lái)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。
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)晶體巖石都非常堅(jiān)硬，但也有例外，最常見(jiàn)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。
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。
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?，這些水分也會(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。
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(wú)法克服表面張力，從而穩(wěn)穩(wěn)地附著在孔隙表面上。
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