21.Farming emerged as a survival strategy because man had been obliged
A) to give up his former way of life
B) to leave the coastal areas
C) to follow the ever-shifting vegetation
D)to abandon his original settlementª¤

22.Earth scientists have come to understand that climate.
A) is going through a fundamental change
B) has been getting warmer for 10,000 years
C) will eventually change from hot to cold
D)has gone through periodical changesª¤

23.Scientists belleve that human evolution .
A) has seldom been accompanied by climatic changes
B) has exerted little influence on climatic changes
C) has largely been effected by climatic changes
D)has had a major impact on climatic changes

24.Evidence of past climatic changes indicates that .
A) human activities have accelerated changes of Earth's environment
B) Earth's environment will remain mild despite human interference
C) Earth's climate is bound to change significantly in the future
D) Earth's climate is unlikely to undergo substantial changes in the future

25.The message the author wishes to convey in the passage is that .
A) human civilization remains glorious though it is affected by climatic changesª¤
B) mankind is virtually helpless in the face of the dramatic changes of climate
C) man has to limit his activities to slow down the global warming process
D) human civilization will continue to develop in spite of the changes of nature

 26.In the eyes of the author,an odd phenomenon nowadays is that .ª¤
A)the Duchess of Windsor is regarded as a woman of virtue
B)looking slim is a symbol of having a large fortune
C)being thin is viewed as a much desired dquality
D)religious people are not necessarily virtuous
ª¤ 
27.Swept by the prevailing trend,the author.
A) had to go on a diet for the greater part of her life
B) could still prevent herself from going off the track
C) had to seek help from rich distant relatives
D) had to wear highly fashionable clothes

28.In human history,people's views on body weight.
A) were closely related to their religious beliefs
B) changed from time to time
C) varied between the poor and the rich
D) led to different moral standardsª¤
 
29.The author criticizes women's obsession with thinness.
A) from an economic and educational perspective
B) from sociological and medical points of view
C) from a historical and religious standpoint
D) in the light of moral principles
 
30.What's the author's advice to women who are absorbed in the idea of thinness?
A) They should be more concerned with their overall lifestyle.
B) They should e more watchful for fatal diseases.
C) They should gain weight to look healthy.
D) They should rid themselves of fantasies about designer clothes.