Living dunes

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题目与答案

1. 27 Paragraph A
   • shaping and reforming
   • causes of desertification
   • need combination of specific conditions
   • potential threat to industry and communication
   • an old superstition demystified
   • differences and similarities

   答案：potential threat to industry and communication

   原文定位：dunes can roll over trees and buildings, march across highways, devour vehicles, threaten crops and factories;Preventing sand dunes from overwhelming cities and agricultural areas has become a priority

   同义替换：「threat to industry and communication」↔「march across highways, devour vehicles」

2. 28 Paragraph B
   • shaping and reforming
   • causes of desertification
   • need combination of specific conditions
   • potential threat to industry and communication
   • an old superstition demystified
   • differences and similarities

   答案：commonest type of dune

   原文定位：The crescentic barchan dune is the most common type of sand dune

   同义替换：「commonest」↔「most common」

3. 29 Paragraph C
   • shaping and reforming
   • causes of desertification
   • need combination of specific conditions
   • potential threat to industry and communication
   • an old superstition demystified
   • differences and similarities

   答案：need combination of specific conditions

   原文定位：Bagnold noted that a sand dune generally needs the following three things to form

   同义替换：「combination of specific conditions」↔「three things to form」

4. 30 Paragraph D
   • shaping and reforming
   • causes of desertification
   • need combination of specific conditions
   • potential threat to industry and communication
   • an old superstition demystified
   • differences and similarities

   答案：a continuous cycling process

   原文定位：The repeating cycle of sand inching up the windward side to the dune crest, then slipping down the dune’s slip face allows the dune to inch forward

   同义替换：「continuous」↔「repeating」

5. 31 Paragraph E
   • shaping and reforming
   • causes of desertification
   • need combination of specific conditions
   • potential threat to industry and communication
   • an old superstition demystified
   • differences and similarities

   答案：shaping and reforming

   原文定位：Depending on the speed and direction of the wind and the weight of the local sand, dunes will develop into different shapes and sizes;Once formed, a dune can grow, change shape, move with the wind and even breed new dunes

   同义替换：「reforming」↔「change」

6. 32 Paragraph F
   • shaping and reforming
   • causes of desertification
   • need combination of specific conditions
   • potential threat to industry and communication
   • an old superstition demystified
   • differences and similarities

   答案：an old superstition demystified

   原文定位：When the thirteenth century explorer Marco Polo encountered the weird and wonderful noises made by desert sand dunes, he attributed them to evil spirits;believe they can now explain the exact mechanism behind this acoustic phenomenon

   同义替换：「old superstition」↔「attributed them to evil spirits」，「demystified」↔「explain the exact mechanism」

7. 33 Paragraph G
   • shaping and reforming
   • causes of desertification
   • need combination of specific conditions
   • potential threat to industry and communication
   • an old superstition demystified
   • differences and similarities

   答案：replicating the process in laboratory

   原文定位：The group hauled sand back to the laboratory and set it up in channels with automated pushing plates. The sands still sang

8. 34 _____ dune is said to have long ridges that can extend hundreds of miles.

   答案：linear

   原文定位：The linear dune is straighter than the crescentic dune with ridges as its prominent feature. Unlike crescentic dunes, linear dunes are longer than they are wide—in fact, some are more than 100 miles (about 160 kilometers) long

   同义替换：「extend hundreds of miles」↔「more than 100 miles (about 160 kilometers) long」

9. 35 According to Bagnold, an _____ is needed to stop the sand from moving before a dune can form.

   答案：obstacle

   原文定位：a wind or breeze to move the grains of sand; and an obstacle, which could be as small as a rock or as big as a tree, that causes the sand to lose momentum and settle

   同义替换：「stop the sand from moving」↔「causes the sand to lose momentum and settle」

10. 36 Stéphane Douady believes the singing of dunes is not a spiritual phenomenon, but purely _____.

    答案：acoustic

    原文定位：believe they can now explain the exact mechanism behind this acoustic phenomenon

    同义替换：「spiritual」↔「acoustic」，「purely」↔「exact mechanism」

11. There are many different types of dunes, two of which are most commonly found in deserts throughout the world, the linear dune and the 37_____ dune, sometimes also known as the crescentic dune.

    答案：barchan

    原文定位：He recognised two basic dune types, the crescentic dune, which he called “barchan,” and the linear dune;The crescentic barchan dune is the most common type of sand dune

    同义替换：「also known as」↔「which he called」

12. It`s been long known that in some places dunes can even sing and the answer lies in the sand itself. To produce singing sand in lab, all the sands must have similar 38_____ .

    答案：shape

    原文定位：To make the booming sound, the grains have to be of a small range of sizes, all alike in shape: well-rounded

    同义替换：「similar」↔「alike」

13. And scientists have discovered that the size of the sand can affect the 39_____ of the sound.

    答案：tone

    原文定位：Douady’s key discovery was that this synchronised frequency;which deter-mines the tone of sound;is the result of the grain size. The larger the grain, the lower the key

    同义替换：「affect」↔「determine」，「sand」↔「grain」

14. But the function of the varnish composed by a mixture of 40_____ still remains puzzling.

    答案：minerals

    原文定位：Douady also discovered that the singing grains had some kind of varnish or a smooth coating of various minerals: silicon, iron and manganese

    同义替换：「composed」↔「coating」，「mixture」↔「various」，「remains puzzling」↔「unsure exactly what role」