TPO59听力Lecture3原文+MP3+题目+答案下载

TPO59听力Lecture3原文+MP3+题目+答案下载

TPO59听力Lecture3原文：

listen to part of a lecture in a geology class. the professor is discussing mass wasting. remember, mass wasting is our geological term for movements of land. you know some already like landslides which are dramatic and might get attention in the news. I mean rock moving at almost 300 kilometers per hour would get your attention right. and there are rock falls also you're probably well acquainted with mass wasting associated with steep hills and mountains. But what about creep?

well, creep is another type of mass wasting. And it is by a long shot, the more common process, mainly because there are a lot more gentle hills or slopes. The term i'll use creep is caused by the same things as other mass movements. Gravity is ultimately responsible, and water affects movement. but creep happens slowly. That is, the soil moves slowly, only a few centimeters to a meter downhill in a year. so how does creep happen? Basically in a freeze thaw cycle, waiter, cold followed by summer heat and so on. let's take a look at the diagram in your book. when the Top layer of soil freezes in winter, it expands, so it pushes up and away from the bedrock layer beneath it. then when the ground warms up in the spring, when it thaws, everything contracts. but those little loose bits of soil on the Top don't go back to their original position. as the arrows show, they follow just a bit farther down the slope. Thanks to gravity, this movement is almost imperceptible, and it's not exciting. I mean, you'll never see it on a tv show about the dangerous forces of nature.

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TPO59听力Lecture3题目：

1. What is the lecture mainly about?

A. The various well-known effects of mass wasting

B. The processes involved in slower types of mass wasting

C. The characteristics of mass wasting in permafrost regions

D. The practice of building in areas where mass wasting occurs

2. What is one condition that the professor mentions that is necessary for creep to occur?

A. A hill or mountain has a steep slope

B. Water is present to move loose soil down the slope

C. There must be trees growing on the side of the slope

D. There is a soil layer that expands and contracts on a periodic basis

3. According to the professor, how is solifluct ion different from creep?

Click on 2 answers

A. Solifluction requires less soil moisture t han creep

B. Solifluction is more difficult to measure

C. Solifluction moves soil in one mass

D. Solifluction requires cold temperatures

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