答案及解析：
1． 文章標題分析：Soot （煤灰） and Snow：a Hot Combination
根據(jù)標題內(nèi)容可以判斷該文章與自然環(huán)境（環(huán)境污染）有關。
2．被選項分析：
A Soot’s Role in Changes in the Climate and the Atmosphere
B Observations of Warming in the Northern Hemisphere
C Explanation of Increased Warming Effect Caused by Soot
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
分析：被選項中都涉及到了文章標題所揭示的核心詞，劃線結(jié)構(gòu)是小標題中的核心結(jié)構(gòu)，也是可以用作答案線索的結(jié)構(gòu)。
直接解題：
A Soot’s Role in Changes in the Climate and the Atmosphere
B Observations of Warming in the Northern Hemisphere
C Explanation of Increased Warming Effect Caused by Soot
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
1． Paragraph 3 __.
Soot in areas with snow and ice may play an important role in climate change．Also，if snow and ice- covered areas begin melting，the warming effect increases，as the soot becomes more concentrated on the snow surface．”This provides a positive feedback, as glaciers and ice sheets melt，they tend to get even dirtier,” said Dr．James Hansen，a researcher at NASA's Goddard Institute for Space Studies．New York．
1．C． 分析：段首句的大意和用詞似乎在暗示A是答案。但是在下文中沒有具體提到soot是如何改變氣候的（排除A）。段落中soot出現(xiàn)了兩次，因此重點注意包含soot的被選項： C和E。段落中沒有提到有關“煤灰散發(fā)”的問題，所以排除E，選擇C。
提示：在借助段首句內(nèi)容的時候判斷答案的時候還應該掃視一下全文。
A Soot’s Role in Changes in the Climate and the Atmosphere
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
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：因為段落中soot出現(xiàn)了兩次，因此重點注意包含soot的被選項： A和E，同樣段落中沒有提到有關“煤灰散發(fā)”的問題，所以判斷A是答案（段落最后一句（觀點句）的含義與A一致）
提示：“避重就輕法”—段首句復雜則看段未句。
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：因為段落中gas出現(xiàn)了兩次，因此重點注意包含gas的被選項：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‘溫室效應是在過去的世紀中造成氣候變暖的主要原因’這個事實））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
1． 文章標題分析：Soot （煤灰） and Snow：a Hot Combination
根據(jù)標題內(nèi)容可以判斷該文章與自然環(huán)境（環(huán)境污染）有關。
2．被選項分析：
A Soot’s Role in Changes in the Climate and the Atmosphere
B Observations of Warming in the Northern Hemisphere
C Explanation of Increased Warming Effect Caused by Soot
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
分析：被選項中都涉及到了文章標題所揭示的核心詞，劃線結(jié)構(gòu)是小標題中的核心結(jié)構(gòu)，也是可以用作答案線索的結(jié)構(gòu)。
直接解題：
A Soot’s Role in Changes in the Climate and the Atmosphere
B Observations of Warming in the Northern Hemisphere
C Explanation of Increased Warming Effect Caused by Soot
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
1． Paragraph 3 __.
Soot in areas with snow and ice may play an important role in climate change．Also，if snow and ice- covered areas begin melting，the warming effect increases，as the soot becomes more concentrated on the snow surface．”This provides a positive feedback, as glaciers and ice sheets melt，they tend to get even dirtier,” said Dr．James Hansen，a researcher at NASA's Goddard Institute for Space Studies．New York．
1．C． 分析：段首句的大意和用詞似乎在暗示A是答案。但是在下文中沒有具體提到soot是如何改變氣候的（排除A）。段落中soot出現(xiàn)了兩次，因此重點注意包含soot的被選項： C和E。段落中沒有提到有關“煤灰散發(fā)”的問題，所以排除E，選擇C。
提示：在借助段首句內(nèi)容的時候判斷答案的時候還應該掃視一下全文。
A Soot’s Role in Changes in the Climate and the Atmosphere
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
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：因為段落中soot出現(xiàn)了兩次，因此重點注意包含soot的被選項： A和E，同樣段落中沒有提到有關“煤灰散發(fā)”的問題，所以判斷A是答案（段落最后一句（觀點句）的含義與A一致）
提示：“避重就輕法”—段首句復雜則看段未句。
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：因為段落中gas出現(xiàn)了兩次，因此重點注意包含gas的被選項：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‘溫室效應是在過去的世紀中造成氣候變暖的主要原因’這個事實））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