E Ways to Reduce Soot Emission
F Greenhouse Gases as the Main Factor of G1obal Warming
2. Paragraph4 __
(Hansen found soot’s effect on snow albedo (solar energy reflected back to space)，which may be contributing to trends toward early springs in the Northern Hemisphere，such as thinning Arctic sea ice，melting glaciers and permafrost)。Soot also is believed to play a role in changes in the atmosphere above the oceans and land.
2.A.分析：因?yàn)槎温渲衧oot出現(xiàn)了兩次，因此重點(diǎn)注意包含soot的被選項(xiàng)： A和E，同樣段落中沒有提到有關(guān)“煤灰散發(fā)”的問題，所以判斷A是答案(段落最后一句(觀點(diǎn)句)的含義與A一致)
提示：“避重就輕法”—段首句復(fù)雜則看段未句。
B Observations of Warming in the Northern Hemisphere
C Effect to Reduce Snow Albedo (反照率)
E Ways to Reduce Soot Emission
F Greenhouse Gases as the Main Factor of G1obal Warming
3. Paragraph 6 __。
Hansen cautioned，although the role of soot in altering global climate is substantial，it does not alter the fact that greenhouse gases are the primary cause of climate warming during the past century.Such gases are expected to be the largest climate forcing for the rest of this century.
3. F. 分析：因?yàn)槎温渲術(shù)as出現(xiàn)了兩次，因此重點(diǎn)注意包含gas的被選項(xiàng)：F.而F中的內(nèi)容正好與段首句中的核心結(jié)構(gòu)(it does not alter the fact that greenhouse gases are the primary cause of climate warming during the past century(它沒有改變‘溫室效應(yīng)是在過去的世紀(jì)中造成氣候變暖的主要原因’這個事實(shí)))一致。
B Observations of Warming in the Northern Hemisphere
C Effect to Reduce Snow Albedo (反照率)
E Ways to Reduce Soot Emission
4.Paragraph 7 __。
The researchers found that observed warming in the Northern Hemisphere was large in the winter and spring at middle and high latitudes.(These observations were consistent with the researchers’climate model simulations， which showed some of the 1argest warming effects occurred when there were heavy snow cover and sufficient sunlight.)
4. B.分析：段首句中出現(xiàn)了Northern Hemisphere，而接下來的句子中出現(xiàn)了“These observations”，這些詞都被包含在B中，因此判斷B是答案。
A produces much more global warming than a carbon-dioxide forcing of the same magnitude
B contributed to 25 percent of observed global warming
C can produce greenhouse gases