下面的短文后有两项测试任务：(1)第23——26题要求从所给的6个选项中为第2——5段的每段选择l个最佳标题;(2)第27——30题要求从所给的6个选项中为每个句子确定1个最佳选项。

　　Global Warming

(1) Smoke is clouding our view of global warming, protecting the planet from perhaps three-quarters of the greenhouse (温室) effect. That might sound like good news, but experts say that as the cover diminishes in coming decades, we are facing a dramatic increase of warming that could be two or even three times as great as official best guesses.

(2) This was the dramatic conclusion reached last week at a workshop in Dahlem, Berlin, where top atmospheric scientists got together, including Nobel prize winner Paul Crutzen and Swedish scientist Bert Bolin, former chairman of the UN's Intergovemmental Panel on Climate Change (IPCC).

(3) IPCC scientists have suspected for a decade that aerosols (浮质) of smoke and other particles from burning rainforest, crop waste and fossil fuels are blocking sunlight and counteracting the warming effect of carbon dioxide (二氧化碳) emissions. Until now, they reckoned that aerosols reduced greenhouse warming by perhaps a quarter, cutting increases by 0.2℃. So the 0.6℃ of warming over the past century would have been 0.8℃without aerosols.

(4) But the Berlin workshop concluded that the real figure is even higher--aerosols may have reduced global warming by as much as three-quarters, cutting increases by 1.80C. If SO, the good news is that aerosols have prevented the world getting almost two degrees warmer than it is now. But the bad news is that the climate system is much more sensitive to greenhouse gases than previously guessed.

(5) As those gases are expected to continue accumulating in the atmosphere while aerosols stabilize or fall, that means "dramatic consequences for estimates of future climate change",the scientists agreed in a draft report from the workshop.

23——26概括大意

23. Paragraph 2 __________

24. Paragraph 3 __________

25. Paragraph 4 __________

26. Paragraph 5 __________

A. Atmospheric scientists

B. The calculations made at the berlin workshop

C. The previous calculations of the effect of aerosols

D. The scientists' agreement

E. The authoritative conclusion

F. Greenhouse gases

27——30完成句子

27. When the cover diminishes in the coming decades, temperature __________.

28. The conclusion reached at the Berlin workshop __________.

29. The Berlin workshop concluded that the real figure __________.

30. The increase of greenhouse gases __________.

A. will influence future climate change

B. was somewhat surprising

C. will rise rapidly

D. was known to us all

E. was much higher than had been expected

F. will drop dramatically

参考答案：

23.E。文章第三段指出，结论是由杰出的大气科学家得出的。“杰出的科学家”即权威科学家。

24.C。文章第三段提到了对浮质所产生的影响进行的计算。这个计算先于第四段所提及的计算，因而被称为“先前的”计算。

25.B。文章第四段开头指出，“然而，柏林讨论会得出的结论是，真正的数字比这还要高——浮质可能已经把全球气候变暖的情况减少了3/4。”因此，本段讲的是柏林讨论会的计算。

26.D。第五段讲的是科学家们关于浮质对气候变化影响的一致性的看法。

27.C。文章第一段指出，随着在未来几十年里这种烟雾覆盖物的不断减少，我们会面临惊人的气候变暖的情况，也就是说，覆盖物减少，气温会迅速升高。

28.B。柏林讨论会的结论有点令人吃惊，因为这个结论认为，浮质可能已经把全球气候变暖的情况减少了3/4，这个数字是惊人的。

29.E。文章第四段指出，“然而，柏林讨论会得出的结论是，真正的数字比这还要高。”“比这还要高”是说比第三段推测的数字要高，也就比人们预期的要高。

30.A。文章的最后一段提到了这个问题：这些气体(温室气体)在大气里不断聚积对未来气候变化的预测产生惊人的结果。