上面的句子说“越来越多的专家认为最快在2010年将会是石油供应的高峰期，随后是天然气的高峰期。他们认为石油和天然气的总量在3，500billion barrels左右，IPCC乐观的估计额是5，0003，500billion barrels”， 因此判断D 是答案。
4. D. 分析：利用问题句中的特征结构Nebojsa Nakicenovi作为答案线索，有两个被选项中都提到了IPCC，因此也利用这个词作为答案线索，这样在文章找到答案相关句：
Nebojsa Nakicenovic, an energy economist（经济学家） at the University of Vienna, Austria who headed（带领） the 80-strong（实足的）（有80人的） IPCC team that produced the forecasts, says the panel（小组）'s work still stands（有效）.该句说“Nebojsa Nakicenovic认为IPCC小组的工作仍然站得住脚， 是客观的”， 因此排除C.
He says they factored in （把……计算在内）a much broader（广泛的） and internationally accepted （被接受的）range （范围）of oil and gas estimates than the “conservative（保守的）” Swedes.该句说“同保守的瑞典人项比， 他们（IPCC小组）把范围更广， 国际认定的燃料储备考虑在内”， 因此可以得出的结论是：IPCC小组在对燃料进行估算上比瑞典人更乐观。
这道体题也可以借助排除法解答：
Even if oil and gas run out, “there's a huge amount of coal underground that could be exploited”, he says that burning coal could make the IPCC scenarios come true, but points out that such a switch would be disastrous. Coal is dirtier than oil and gas and produces more CO2 for each unit of energy, as well as releasing （释放）large amounts of particulates（微粒）.
该划线句说“煤（化石燃料）比石油和天然气更具有污染性”， 因此排除A. 而文章中根本就没有具体提到“green fuel”是什么, 因此B 也不是答案，答案只能是D.
5.B. 分析：Nakicenovic提出的断言出现在文章最后的两段文字中， 被选项中两处提到了switch一词，所以利用这个词作为答案线索，
Nebojsa Nakicenovic, an energy economist at the University of Vienna, Austria who headed the 80-strong IPCC team that produced the forecasts, says the panel's work still stands. He says they factored in a much broader and internationally accepted range of oil and gas estimates than the “conservative” Swedes.
Even if oil and gas run out, “there's a huge amount of coal underground that could be exploited”, he says that burning coal could make the IPCC scenarios come true, but points out that such a switch would be disastrous. 划线句前部分结构中揭示： switch是指从使用石油和天然气到使用煤的转变。 接下来的句子说：Coal is dirtier than oil and gas and produces more CO2 for each unit of energy, as well as releasing large amounts of particulates.（煤比原油和天然气更具有污染性）， 该句暗示煤的燃烧会造成更大的环境灾难， 因此判断B是答案。
