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THE MAN GIVES HIS OPINION OF THE CHANGE IN THE GRADING POLICY
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TOEFL audioscript
THE MAN GIVES HIS OPINION OF THE CHANGE IN THE GRADING POLICY.
STATE HIS OPINION AND THE REASONS HE GIVES FOR HOLDING IT. Page 386 [ mp3 164-165] Question 3. Listen to the passage. Then respond to the question. (Professor) OK today, I’ll be talking about glaciers and, in particular, how glaciers are formed. So first of all, do you know what a glacier is? Well, a glacier is a mass of ice, but there’s more to it than that. A glacier is a mass of ice that’s moving. Now glaciers form where snow accumulates, um, where more snow falls than melts, so it piles up. If all the snow melts every year in a particular place, a glacier can’t form there. Or even if all of the snow doesn’t melt, as long as the average amount of snow that accumulates is less than or equal to the average amount that melts then there will be no glacier. And there needs to be considerable accumulation. If there’s only a small amount of accumulation, then a glacier can’t form because there has to be considerable weight. So, when the amount of snow that falls year after year exceeds the amount that melts every year, eventually all of the snow accumulates to an extent that there’s pressure on the snow underneath, enough pressure to transform the loose snowflakes into ice crystals. The weight of the accumulated snow causes the snow to compress into ice crystals, and with more and more pressure, the smaller ice crystals pack together to create even larger crystals. Now, this ice is a solid substance, or more or less solid. There are air bubbles trapped in the ice, but mostly it is solid ice. Nevertheless, as LPREP IBT 3 E AudioScript 104 tons and tons of snow continue to accumulate and to be compacted into ice, the solid ice begins to flow slowly because of the enormous pressure. In other words, even though it’s solid ice, under high pressure, it can flow like toothpaste. As the ice begins to flow away from the increasing pressure of the accumulating snow and ice above, it begins to move downhill or away from a central place. At this point in time, when the ice begins to move, a glacier is born. Download 0.63 Mb. Do'stlaringiz bilan baham: |
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