大学英语四级阅读二十一

大学英语四级阅读二十一,本站还有更多关于英语四六级考试时间,英语四六级考试成绩查询,英语四六级考试试题,历年英语四六级考试试题及答案解析的文章。
  Flying over a desert area in an airplane, two scientists looked down with trained eyes at trees and bushes. After an hour's flight one of the scientists wrote in his book, 'Look here for probable metal' Scientists in another airplane, flying over a mountain region,sent a message to other scientists on the ground,'Gold possible.' Walking across hilly ground, four scientists reported,'This ground should be searched for metals.' From an airplane over a hilly wasteland a scientist sent back by radio one word,'Uranium'.

    None of the scientists had X-ray eyes: they had no magic powers for looking down below the earth's surface. They were merely putting to use one of the newest methods of location minerals in the ground——using trees and plants as signs that certain minerals may lie beneath the ground on which the trees and plants are growing.

    This newest method of searching for minerals is based on the fact that minerals deep in the earth may affect the kind of bushes and trees that grow on the surface.

    At Watson Bar Creek, a brook six thousand feet high in the mountains of British Columbia, Canada,a mineral search group gathered bags of tree seeds. Boxed were filled with small banches from te trees. Roots were dug and put into boxes. Each bag and box was carefully marked. In a scientific laboratory the parts of the forest trees were burned to ashes and tested .Each small part was examined to learn whether there were minerals in it.

    Study of the roots , branches,and seeds showed no silver. But there were small amounts of gold in the roots and a little less gold in the branches and seeds. The seeds growing nearest to the tree trunk had more gold than those growing on the ends of the branches.

    If the trees had not indicated that there was gold in the ground, the scientists would not have spent money to pay for digging into the deeper. They did dig and found more fold below. They dug deeper. They found large quantities of gold.

    1.Scientists were flying over a desert or hilly wasteland or a mountain region in order to search for _____ in the ground.

    a.gold

    b.silver

    c.metals

    d.minerals

    2.The study of trees,branches and roots indicates that_______.

    a.there were larger amounts of gold in the branches than in the seeds.

    b.there were small amounts of gold in the roots than in the branches

    c.there were larger amounts of gold in the seeds growing nearest to the tree trunk than seeds growing on the ends of branches.

    d.there were more gold in the branches than in the roots

    3.Which is the best title ?

    a.Scientists searching for metals with sepcial power

    b.New methods of searching for minerals

    c.Gold could be found by trees and plants

    d.A new method of searching for minerals——using trees and plants

    4.Which of the following is not mentioned as part of a tree that can help find minerals?

    a.leaves

    b.roots

    c.branches

    d.seeds

    5.The scientists were searching for minerals by using ______.

    a.X-ray

    b.magic power

    c.a special instrument

    d.trained eyes

    21/200答案:dcdad

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