北京新航道衷心为为广大考生提供托福考试及其托福培训的相关资料及其指导。在托福考试中，阅读理解是重头戏，对考生来说得分容易失分也容易，所以说要把握好阅读理解很重要。考生很头疼，怎样才能阅读能力并在托福考试中获得好的成绩呢? 在这里，我们和考生一起通过对过去真题钟阅读部分做详解，来总结经验，多积累。希望通过这些回顾和总结帮助考生来攻克阅读的难关。

　　Ground water原文分析

　　TPO1-1：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.

　　1.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 from circulating.

　　C.It absorbs most of the water it contains from rivers.

　　D.It has the capacity to store large amounts of water.

　　2.The word “incredible” in the passage is closest in meaning to_____

　　A.Unbelievable

　　B.Comforting

　　C.Confusing

　　D.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_____

　　A.Far away

　　B.Partly visible

　　C.Hidden

　　D.Discovered

　　4.According to paragraph 2，where is groundwater usually found?

　　A.Inside pieces of sand and gravel

　　B.On top of beds of rock

　　C.In fast rivers that are flowing beneath the soil

　　D.In spaces between pieces of sediment

　　5.The phrase “glacial outwash” in the passage refers to_____

　　A.Fast rivers

　　B.Glaciers

　　C.The huge volumes of water created by glacial melting

　　D.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 A mountain valley

　　B.Flat land

　　C.A lake floor

　　D.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_____

　　A.Cover

　　B.Change

　　C.Separate

　　D.Surround

　　努力总会有收获的，阅读理解是需要长期的练习积累才能的，所以考生要坚持下来，要用心且找到适合自己的方法，及早发现缺陷，扬长补短，取得一个好成绩，北京新航道在这里预祝大家能够发挥出自己的状态，取得好成绩。

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