Dust and the American west

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题目与答案

1. 1 Jason Neff discovered there had been a dramatic rise in dust levels in the second half of the nineteenth century.
   • TRUE
   • FALSE
   • NOT GIVEN

   答案：TRUE

   原文定位：Atmospheric dust was minimal throughout those five millennia until the mid-19th century, he says, but then, 'from about 1860 to 1900, dust deposition rates shot up

   同义替换：「dramatic rise in dust levels」↔「dust deposition rates shot up」，「second half of the nineteenth century」↔「from about 1860 to 1900」

2. Jason Neff:

   ·found that 10_____ in the Colorado region contained dust.

   答案：lake sediments

   原文定位：When Neff first discovered dust in Colorado lake sediments laid down in the 19th century, he was initially unsure where it came from

   同义替换：「found」↔「discovered」

3. ·examined the dust for its chemical content as well as its 11_____

   答案：size

   原文定位：But after investigating the size and chemical composition of the dust, Neff was clear that it mostly came from the American Southwest, mainly Arizona and New Mexico

   同义替换：「examined」↔「investigating」，「content」↔「composition」，「as well as」↔「and」

4. ·concluded that the dust was from the American Southwest.

   ·found that dust affects mountain environments by bringing in 12_____ that are not normally found there causing faster seasonal snowmelt.

   答案：nutrients

   原文定位：They carry nutrients with them into areas which previously evolved and survived without them

   同义替换：「bringing」↔「carry」，「not normally found there」↔「previously evolved and survived without them」

5. ·argues that dust is partly to blame for the gradual disappearance of some 13_____ and snow.

   答案：glaciers

   原文定位：The loss of snow and the shrinking of glaciers across the American West in the past century has been dramatic;Neff's findings suggest that dust may also contribute

   同义替换：「gradual disappearance」↔「shrinking」，「dust is partly to blame」↔「dust may also contribute」

6. 2 The Anasazi civilization disappeared due to the impact of dust in the atmosphere.
   • TRUE
   • FALSE
   • NOT GIVEN

   答案：FALSE

   原文定位：There was a near-permanent drought between 900 and 1300 which was so intense that it destroyed a series of native American civilizations, including the Anasazi;Yet the evidence from the San Juan lakes is that it was not dusty

   同义替换：「disappeared」↔「destroyed」

7. 3 Before cattle were introduced to the American Southwest, large numbers of bison occupied the area.
   • TRUE
   • FALSE
   • NOT GIVEN

   答案：FALSE

   原文定位：Unlike most other parts of the US, there were few grazers in the American Southwest until the Europeans came. No bison and few antelope or deer

   同义替换：「large numbers of bison occupied the area」↔「No bison」

8. 4 The bison population in the Great Plains diminished because European settlers found it easy to hunt them.
   • TRUE
   • FALSE
   • NOT GIVEN

   答案：NOT GIVEN

   原文定位：In the Great Plains to the east and north, bison roamed in vast herds. Their regular grazing had created tough grass, while the herds manured the soil

9. 5 The development of railroads across the US was more expensive than originally expected.
   • TRUE
   • FALSE
   • NOT GIVEN

   答案：NOT GIVEN

   原文定位：The money went into railroads, and herds of cattle and sheep that rode the rails to the wide open pastures

10. 6 The Aztec Land and Cattle Company worked hard to take care of the grazing land it owned.
    • TRUE
    • FALSE
    • NOT GIVEN

    答案：FALSE

    原文定位：Each acre had cost the company a mere 50 cents, and like many other speculators, it was only interested in quick profits and had little incentive to protect the soils from overgrazing

11. 7 Most of the land once owned by the Aztec Land and Cattle Company remains infertile today.
    • TRUE
    • FALSE
    • NOT GIVEN

    答案：TRUE

    原文定位：Such was the damage to the grasslands that even now few of the pastures have recovered

    同义替换：「remains infertile today」↔「even now few of the pastures have recovered」

12. American Southwest: 1860s to present day

    1862-American Homestead Act was passed to encourage settlement in the West.

    1930s - Laws were passed to control the size of 8_____

    答案：cattle herds

    原文定位：It was only in the 1930s, with the passage of the Taylor Grazing Act, that federal authorities finally sought to limit cattle herds

    同义替换：「control」↔「limit」

13. Today Jayne Belnap believes:

    ·soil was not affected by high 9_____

    ·soil was seriously affected by cattle hooves.

    答案：winds

    原文定位：These crusts can survive winds of up to a hundred miles an hour, but cattle hooves break the crust,' says Jayne Belnap, a soil ecologist at the US Geographical Survey, Utah

    同义替换：「soil was not affected by」↔「crusts can survive」，「high」↔「up to a hundred miles an hour」