2009年12月英语六级阅读理解全真模拟题(四)

　　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 settlement

　　24. 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 change

　　23. Scientists believe 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 changes

　　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