2016年6月英语六级阅读每天一练(41)

2021-10-12 13:23:01 · 作者:编辑部  
距离2016年6月英语六级考试还有一个月的时间,这个时候也是大家备考英语六级阅读最好的时机。新东方在线英语六级频道为大家整理了英语

  距离2016年6月英语六级考试还有一个月的时间,这个时候也是大家备考英语六级阅读最好的时机。新东方在线英语六级频道为大家整理了英语六级阅读每天一练,希望可以为大家带来帮助。

  For as long as humans have raised crops as a source of food and other products, insects have damaged them. Between 1870 and 1880, locusts ate millions of dollars' worth of crops in the Mississippi Valley. Today in the United States the cotton boll weevil damages about 300 million dollars' worth of crops each year. Additional millions are lost each year to the appetites of other plant-eating insects. Some of these are corn borers, gypsy moths, potato beetles, and Japanese beetles.

  In modern times, many powerful insecticides(杀虫剂) have been used in an attempt to destroy insects that damage crops and trees. Some kinds of insecticides, when carefully used, have worked well. Yet the same insecticides have caused some unexpected problems. In one large area, an insecticide was used against Japanese beetles, which eat almost any kind of flower or leaf. Shortly afterward, the number of corn borers almost doubled. As intended, the insecticide had killed many Japanese beetles. But it had killed many of the insect enemies of the corn borer as well.

  In another case, an insecticide was used in Louisiana to kill the troublesome fire ant. The insecticide did not kill many fire ants. It did kill several small animals. It also killed some insect enemies of the sugarcane borer, a much more destructive pest than the fire ants. As a result, the number of sugarcane borers increased and severely damaged the sugarcane crop.

  To be sure that one insect pest will not be traded for another when an insecticide is used, scientists must perform careful experiments and do wide research. The experiments and research provide knowledge of the possible hazards an insecticide may bring to plant and animal communities. Without such knowledge, we have found that nature sometimes responds to insecticides in unexpected ways.

  21. An insecticide was used in Louisiana to kill the troublesome______.

  A. corn borer B. Japanese beetle

  B. gypsy moth D. fire ant

  22. While it is not directly stated, the article suggests that______.

  A. insecticides are not dangerous to any small animals

  B. insecticides do not always accomplish their purposes

  C. insecticides are no longer being used to kill insects

  D. insecticides do no harm to people

  23. On the whole, the article tells about______.

  A. the appetites of plant-eating insects B. the best way to kill boll weevils C. the dangers in using insecticides D. the best way to grow crops

  24. Which statement does this article lead you to believe?

  A. All changes are predictable. B. Nothing ever changes in nature.

  C. Nature is not always predictable. D. Nature always serves man well.

  25. Scientists perform careful experiments and do wide research because______.

  A. they must learn to destroy all the insects that we need

  B. they must be sure one insect pest is not traded for another

  C. research keeps them from inventing new insecticide for the crops

  D. research helps them find a way to kill all insects

  21. D 22. B 23. C 24. C 25. B

  编辑推荐:

  2016年6月大学英语六级阅读每天一练汇总

【本文为找大学网转载,文章版权归原作者及原出处所有。文章系作者个人观点,不代表大学生在线立场,转载请联系原作者及原出处获得授权。有任何疑问都请联系(kf@zhaodaxue.cn)】
  • 相关阅读

TOPS
  • 日排行/
  • 周排行/
  • 原创