How deserts are formed

文章内容（节选）

完整文章请进入机考练习查看。

题目与答案

1. the reference of irregular movement of particles
   • A
   • B
   • C
   • D
   • E
   • F

   答案：C

   原文定位：Once ejected, these particles move in one of three possible ways, depending on their size, shape and density

2. an account that a productive-land turned into a desert in 20th century
   • A
   • B
   • C
   • D
   • E
   • F

   答案：A

   原文定位：In a state of America in 20th century,a large area of farmland had become desert

3. the types of deserts
   • A
   • B
   • C
   • D
   • E
   • F

   答案：A

   原文定位：Deserts have been defined and classified in a number of ways, generally combining total precipitation, number of days on which this falls, temperature, and humidity, and sometimes additional factors

4. the method of tackling the problems of deserts
   • A
   • B
   • C
   • D
   • E
   • F

   答案：I

   原文定位：Nowadays,new technologies are being applied to help solve desertification problems.Satellites have been put into use to study the impact of people and livestock on earth

5. the effect of migration on desertification
   • A
   • B
   • C
   • D
   • E
   • F

   答案：F

   原文定位：Some nomads take the desert wherever they go

6. the lack of agreement among the scientists about the causes of desertification
   • A
   • B
   • C
   • D
   • E
   • F

   答案：H

   原文定位：Although there is tremendous publicity on the severity of desertification,the researchers have never reached a consensus on the reasons and process of desertification

7. the example of the fatal effects of farming practice
   • A
   • B
   • C
   • D
   • E
   • F

   答案：D

   原文定位：Since the raising of most crops necessitates the prior removal of the natural vegetation, crop failures leave extensive tracts of land devoid of a plant cover and susceptible to wind and water erosion

8. 21 It is difficult to ascertain where the deserts begin in some areas.
   • TRUE
   • FALSE
   • NOT GIVEN

   答案：TRUE

   原文定位：in other areas,the borders of deserts cannot be determined

9. 22 Farming animals will increase soil erosion.
   • TRUE
   • FALSE
   • NOT GIVEN

   答案：TRUE

   原文定位：The consequences of an excessive number of livestock grazing in an area are the reduction of the vegetation cover and the trampling and pulverization of the soil. This is usually followed by the drying of the soil and accelerated erosion

10. 23 The most common cause of desertification is the lack of rainfall.
    • TRUE
    • FALSE
    • NOT GIVEN

    答案：FALSE

    原文定位：It is a misconception that the lack of rainfall causes the desertification. Even in some arid areas, the land will recover as soon as rain comes. More desertification is caused by human activities

11. 24 The problems in West Africa are yet to be solved.
    • TRUE
    • FALSE
    • NOT GIVEN

    答案：NOT GIVEN

    原文定位：In the West Africa,a serious desertification causes a large number of people to lose their lives

12. 25 Media is uninterested in the problems of desertification.
    • TRUE
    • FALSE
    • NOT GIVEN

    答案：FALSE

    原文定位：Although there is tremendous publicity on the severity of desertification

13. 26 Technology studying the relationship of people, livestock and desertification is yet to be invented.
    • TRUE
    • FALSE
    • NOT GIVEN

    答案：FALSE

    原文定位：Satellites have been put into use to study the impact of people and livestock on earth