练习

Ⅰ Cloze

Is there a population problem?

　　My answer   1    the question is "YES", there is a problem. The scale of human activities is now so __2__ that we are appreciably  3  the climate and ecosystems in the U.S. and the world.

　　The total impact of people __4__ the environment is proportional __5__ each of two factors:

　　A) The number of people, and

　　B) The _6___ impact of each person.

　　If we are to_  7___ the total impact of people on the global environment, we must address the first, or preferably both, of these  __8__.

　　There are many strong forces that will cause ___9_ growth of the average impact of each person on the global environment. To the  __10__ that people in underdeveloped countries  __11_ increase their material standard of living to levels more like ours, material consumption per capita will grow. So we are left __12__ the imperative of halting population growth, and then of  __13__ the question, "Can this stable population be sustained?"

　　To gain a better  __14__ of the seriousness of the problem, let us review some very elementary  __15__. Let us consider a   __16__ that is experiencing steady growth  _17___ such as 5% per year.

　　First we note that this growing quantity will double   _18__ in a   __19__ time. This _20___ time is found by dividing 70 by the percent growth per year. For example, the doubling time for a steady growth rate of 5% per year is 70 / 5 = 14 years.

　　Second, we note that a few doublings can give enormous numbers. It is convenient to 20  remember that ten doublings causes the growing quantity to increase in size by a factor of approximately 1000: twenty doublings will cause an increase by a factor of 1,000,000, etc.

1. [A]of　　[B]to　　[C]with　　[D]for

2. [A]large　　[B]big　　[C]small　　[D]little

3. [A]effecting　　[B]causing　　[C]affecting　　[D]affiliating

4. [A]with　　[B]of　　[C]to　　[D]on

5. [A]of　　[B]to　　[C]within　　[D]for

6. [A]average　　[B]averagenal　　[C]averaged　　[D]averaging

7. [A]decrease　　[B]reduce　　[C]decline　　[D]deduce

8. [A]truths　　[B]facts　　[C]factors　　[D]elements

9. [A]continued　　[B]continuous　　[C]continual　　[D]continuity

10. [A]scale　　[B]extent　　[C]range　　[D]sphere

11. [A]seek to　　[B]seek　　[C]seek after　　[D]seek for

12. [A]of　　[B]by　　[C]as　　[D]with

13.[A]learning　　[B]studying　　[C]searching　　[D]researching

14.[A]appreciation　　[B]understanding　　[C]awareness　　[D]knowledge

15.[A]arithmetician　　[B]arithmetically　　[C]aristocratic　　[D]arithmetic

16.[A]amount　　[B]quality　　[C]quantity　　[D]number

17. [A]on a rate　　[B]at a rate　　[C]of a rate　　[D]at rate

18.[A]in size　　[B]in number　　[C]in amount　　[D]in measurement

19.[A]given　　[B]suggested　　[C]fixed　　[D]little

20.[A]double　　[B]doubling　　[C]doubled　　[D]doubles