The Formation and Movement of Glacier托福红Delta听力原文翻译及问题答案

The Formation and Movement of Glacier托福红Delta听力原文翻译及问题答案，今天中国教育在线就来为大家分析这个问题。

一、The Formation and Movement of Glacier托福听力原文：

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托福听力中文翻译：

你可能认为大雪是形成冰川的主要条件。但是如果你停下来想一想，你会发现世界上有很多地区有大量的雪，但没有冰川。仅仅下雪是不够的。要形成冰川，雪是不会融化的。必须加以保护。在极冷的北极和南极，有大片地区的降水量极少，实际上属于沙漠。虽然雪很少，但有巨大的冰原，因为真正落下的雪被保存并转化为冰。

当然，很多地方确实有大量的雪，而且它们确实有冰川。。。比如高山。在气候潮湿寒冷的高山上，降雪频繁。在雪线以上，每年的降雪量超过了每年的融化量，因此雪会堆积起来。堆积物最厚的是山谷顶部的凹陷，因为这些位置相对较高且凉爽，并且受到阳光和风的保护。

随着雪在山谷中积聚，它逐渐变成冰。首先，脆弱的雪晶被更多的雪压碎。由于压实、地热和季节性温度波动，有一些融化和再冻结。因此，雪晶被打破，然后被融水浸湿，一次又一次地重新凝结。

随着时间的推移，雪花逐渐变成了谷物。它们变成圆形和颗粒状，就像粗糖的颗粒一样。谷物之间有气穴，将谷物相互连接。这种被称为“冰原”的旧雪通常是在一个完整的冬夏周期后形成的。

积雪实际上是一小块冰。冰原开始重新结晶，最终结合并结晶成固体冰——冰川。所发生的是，小颗粒聚结形成巨大的联锁冰晶体，空气被困在晶体内形成气泡。最后，它是纯冰，所有的空气都被挤出了。冰川下山有助于晶体生长，因为这种运动有助于压缩空气。

随着山谷顶部的山谷被雪填满，变成冰，山谷扩大，岩壁被移动的冰雕刻出来。随着新雪的加入，冰雪团的下部会凸出，有点像泥饼。随着冰块不断膨胀，部分冰越过山谷边缘，开始沿着山谷向下移动。大冰川的移动速度通常比小冰川快。此外，在夏季，冰层的运动速度更快，此时冰层下方和周围存在更多的融水，以润滑冰层并使其浮出水面。

大多数山谷冰川以。。。哦每天几英寸到几英尺之间。但一些被称为“汹涌冰川”的冰川每天可以移动300英尺。阿拉斯加州和西北地区至少有200条这样的冰川在不断膨胀。这种激增是由多种情况引起的，比如。。。哦突然调整顶部雪荷载的增加，或更可能的是，由于温度升高导致融水产生的增加。融化水较多的冰川润滑性较好，移动速度往往比干燥的冰川更快。在非常寒冷的气候中，冰川由于缺乏融化而相当干燥。由于水量很小，因此冰川滑动的速度不会很快。

在温暖的气候中，冰川被融水更好地润滑。它们还会造成更多的侵蚀，更多的谷底雕刻。这是因为在融冻循环期间，冰川的一部分冻结到山谷的底部和两侧，然后，随着冰的移动，大块的冰川将岩石拔出。因此，你可以看到为什么气候温暖的冰川对景观的影响比气候非常寒冷的冰川更大。

三、The Formation and Movement of Glacier托福听力问题：

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托福听力答案：

A1:正确答案：BC

A2:正确答案：A

A3:正确答案：C

A4:正确答案：BABAA

A5:正确答案：A

A6:正确答案：B

>> 雅思 托福 免费测试、量身规划、让英语学习不再困难<<