The Formation and Movement of Glacier托福紅Delta聽力原文翻譯及問題答案

The Formation and Movement of Glacier托福紅Delta聽力原文翻譯及問題答案，今天中國教育在線就來為大家分析這個問題。

一、The Formation and Movement of Glacier托福聽力原文：

You might expect that heavy snowfall is the main requirement for the formation of a glacier.But if you stop and think about it,you’ll realize there are lots of areas of the world that receive huge amounts of snow but have no glaciers.Snowfall alone isn’t enough.For a glacier to form,the snow can’t melt.It has to be conserved.In the extremely cold Arctic and Antarctic,there are large areas that receive minimal precipitation and actually qualify as desert.Although there’s little snow,there are massive ice sheets because the snow that does fall is conserved and transformed into ice.

Of course,lots of places do get large amounts of snow,and they do have glaciers...high mountains,for example.In high mountains where the climate is humid and cold,snowfall is frequent.Above the snowline,the annual snowfall exceeds the annual melting,so snow builds up.The accumulation is thickest in the hollows at the heads of valleys,because these locations are relatively high and cool,and are protected from sun and wind.

As snow accumulates in a hollow,it’s gradually converted to ice.First,the fragile snow crystals break as they’re compressed by the weight of more snow settling on top of them.There’s some melting and refreezing because of compaction,earth heat,and seasonal temperature fluctuations.So,the snow crystals are broken,then they’re wetted by meltwater,and refrozen,over and over again.

Gradually,over time,the snowflakes change into grains.They become rounded and granular,like the grains of coarse sugar.There are pockets of air between the grains,connecting the grains to one another.This old snow,called“firn,”is generally created after one complete winter-summer cycle.

Firn is actually bits of ice.The firn begins to re-crystallize,and eventually,it combines and crystallizes into solid ice—a glacier.What happens is,the small grains coalesce to form large interlocking crystals of ice,with air trapped as bubbles inside the crystals.In the end,it’s pure ice,with all the air squeezed out.The flow of the glacier down the mountain contributes to crystal growth,as the movement helps to compress the air out.

As the hollow in the valley head fills with snow turning to ice,the hollow enlarges,and the rock walls are carved out by shifting ice.As new snow is added,the lower part of the snow-and-ice mass bulges out,kind of like a mud pie.As the mass continues to bulge,part of the ice moves over the edge of the hollow and starts moving down the valley.Large glaciers usually move faster than small ones.Also,the movement is faster in the summer,when more meltwater is present beneath and around the ice mass to lubricate it and buoy it up.

Most valley glaciers move at a rate of...oh...between a few inches and a few feet a day.But some glaciers—called surging glaciers—can travel as much as 300 feet a day.There are at least 200 of these surging glaciers in Alaska and the Northwest Territories.The surging is caused by a number of conditions,like...oh...sudden adjustment to an increase in the snow load on top,or,more likely,an increase in the production of meltwater due to a rise in temperature.Glaciers that have more meltwater are better lubricated and tend to move faster than drier ones.In very cold climates,glaciers are quite dry because of the lack of melting.The amount of water is slight,so the glacier does not slide as quickly.

In warmer climates,glaciers are better lubricated with meltwater.They also cause more erosion,more carving out of the valley floor.This is because during the melt-freeze cycle,parts of the glacier freeze to the bottom and sides of the valley,and then,as the ice moves on,large chunks of glacier pluck out rock.So you can see why glaciers in warmer climates have a greater impact on the landscape than those in very cold climates.

二、The Formation and Movement of Glacier托福聽力中文翻譯：

你可能認為大雪是形成冰川的主要條件。但是如果你停下來想一想，你會發(fā)現(xiàn)世界上有很多地區(qū)有大量的雪，但沒有冰川。僅僅下雪是不夠的。要形成冰川，雪是不會融化的。必須加以保護。在極冷的北極和南極，有大片地區(qū)的降水量極少，實際上屬于沙漠。雖然雪很少，但有巨大的冰原，因為真正落下的雪被保存并轉化為冰。

當然，很多地方確實有大量的雪，而且它們確實有冰川。。。比如高山。在氣候潮濕寒冷的高山上，降雪頻繁。在雪線以上，每年的降雪量超過了每年的融化量，因此雪會堆積起來。堆積物最厚的是山谷頂部的凹陷，因為這些位置相對較高且涼爽，并且受到陽光和風的保護。

隨著雪在山谷中積聚，它逐漸變成冰。首先，脆弱的雪晶被更多的雪壓碎。由于壓實、地熱和季節(jié)性溫度波動，有一些融化和再凍結。因此，雪晶被打破，然后被融水浸濕，一次又一次地重新凝結。

隨著時間的推移，雪花逐漸變成了谷物。它們變成圓形和顆粒狀，就像粗糖的顆粒一樣。谷物之間有氣穴，將谷物相互連接。這種被稱為“冰原”的舊雪通常是在一個完整的冬夏周期后形成的。

積雪實際上是一小塊冰。冰原開始重新結晶，最終結合并結晶成固體冰——冰川。所發(fā)生的是，小顆粒聚結形成巨大的聯(lián)鎖冰晶體，空氣被困在晶體內形成氣泡。最后，它是純冰，所有的空氣都被擠出了。冰川下山有助于晶體生長，因為這種運動有助于壓縮空氣。

隨著山谷頂部的山谷被雪填滿，變成冰，山谷擴大，巖壁被移動的冰雕刻出來。隨著新雪的加入，冰雪團的下部會凸出，有點像泥餅。隨著冰塊不斷膨脹，部分冰越過山谷邊緣，開始沿著山谷向下移動。大冰川的移動速度通常比小冰川快。此外，在夏季，冰層的運動速度更快，此時冰層下方和周圍存在更多的融水，以潤滑冰層并使其浮出水面。

大多數山谷冰川以。。。哦每天幾英寸到幾英尺之間。但一些被稱為“洶涌冰川”的冰川每天可以移動300英尺。阿拉斯加州和西北地區(qū)至少有200條這樣的冰川在不斷膨脹。這種激增是由多種情況引起的，比如。。。哦突然調整頂部雪荷載的增加，或更可能的是，由于溫度升高導致融水產生的增加。融化水較多的冰川潤滑性較好，移動速度往往比干燥的冰川更快。在非常寒冷的氣候中，冰川由于缺乏融化而相當干燥。由于水量很小，因此冰川滑動的速度不會很快。

在溫暖的氣候中，冰川被融水更好地潤滑。它們還會造成更多的侵蝕，更多的谷底雕刻。這是因為在融凍循環(huán)期間，冰川的一部分凍結到山谷的底部和兩側，然后，隨著冰的移動，大塊的冰川將巖石拔出。因此，你可以看到為什么氣候溫暖的冰川對景觀的影響比氣候非常寒冷的冰川更大。

三、The Formation and Movement of Glacier托福聽力問題：

Q1:What is the lecture mainly about?Click on two answers.

A.The world’s largest glaciers

B.How glaciers are created

C.The movement of glaciers

D.Why glaciers are melting

Q2:What point does the professor make about the snow that forms a glacier?

A.It is conserved.

B.It is light and fluffy.

C.It is denser than ice.

D.It is very dirty.

Q3:Why does the professor say this:

A.To explain why it snows frequently in the mountains

B.To show why mountain scenery attracts many visitors

C.To describe conditions that lead to glacier formation

D.To compare mountain glaciers with Arctic ice sheets

Q4:The professor briefly explains a process that occurs in mountain valleys.Indicate whether each sentence below is a stage in the process.

For each sentence,click in the correct box.

Q5:Why are some glaciers called surging glaciers?

A.They move much faster than other glaciers.

B.They form during one winter-summer cycle.

C.They continuously change form as they move.

D.They add a lot of silt to mountain rivers.

Q6:What can be inferred about glaciers in warmer climates?

A.They are drier than glaciers in very cold climates.

B.They can change the shape of a mountain valley.

C.They are found on only one side of a mountain.

D.They move more quickly during the winter.

四、The Formation and Movement of Glacier托福聽力答案：

A1:正確答案：BC

A2:正確答案：A

A3:正確答案：C

A4:正確答案：BABAA

A5:正確答案：A

A6:正確答案：B

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