5．Rooftops covered with plants-called"green roofs"-could help fight global warming，scientists now suggest．
Green roofs are growing more popular in cities，with the number of green roofs increasing in the United States．In Germany，widely considered the leader in green roofing，some 12percent of all flat roofs are green，with the German green roof industry growing 10to 15percent annually．
These roofs can reduce heating and air conditioning costs，with a roughly 10percent reduction in natural gas usage and a 2percent drop in electricity use for a typical building．Moreover，green roofs last two to three times longer than standard roofs．They also store storm water，which could otherwise exacerbate（加剧）flooding．"They can also bring in birds and butterflies，help improve biodiversity（多样性），"Rowe said．In addition to taking in pollution and noise，the plants in green roofs naturally absorb carbon dioxide，the leading greenhouse gas behind global warming．However，nobody had measured the potential effect of green roofs on carbon dioxide levels until now．
Scientists at Michigan State University found that replacing traditional roofing materials with green roofs in an urban area the size of Detroit，with a population of about one million，would take in more than 55000 tons of carbon．That is roughly similar to getting rid of a year's worth of carbon dioxide sent out by 10000 mid-sized SUVs and trucks．
The challenges green roofs now face in the United States are something about policy and costs．"The government should not necessarily mandate（强制执行） them，but it can provide support for them，just as they do in Germany and elsewhere，"Rowe told Live Science．"And green roofs are more expensive，but only initially．Over time，they're cheaper once you consider their benefits energy-wise．It takes about 11to 14years to break even（不赢不亏）．"
59．Which of the following can be the best title？C
A．Standard Roofs and Green Roofs
B．Green Roofs Are Growing More Popular
C．Green Roofs Help Control Global Warming，Study Finds
D．Advantages of Green Roofs
60．Which of the following is NOT true？B
A．Green roofs can take in the leading greenhouse gas behind global warming．
B．It is easier for green roofs to break than standard roofs．
C．A building with a green roof takes less energy to be heated．
D．Green roofs are of higher building cost．
61．We can learn from the passage thatD．
A．Rowe is not optimistic about the future of green roofs
B．Germany has made it a rule to build green roofs
C．The United States is widely considered the leader in green roofing
D．Green roofs can provide habitats for birds and butterflies
62．The underlined word in the last paragraph is closest in meaning toB．
A．slightly B．at the beginning C．extremely D．in the end．
分析 本文讲了绿色屋顶的发展近况和前景，以及为我们生活环境带来的好处．
解答 CBDB
59．C 主旨大意题．通过整篇文章分析，本文主要讲了绿色房顶可以吸收二氧化碳等温室气体，这有利于帮助我们控制全球变暖，因此答案选C．
60．B 细节理解题．本题可用排除法．根据文章第三段倒数第二句In addition to taking in pollution and noise，the plants in green roofs naturally absorb carbon dioxide，the leading greenhouse gas behind global warming．可知A项表述正确；根据文章第三段第一句These roofs can reduce heating and air conditioning costs，with a roughly 10 percent reduction in natural gas usage and a 2 percent drop in electricity use for a typical building可知，C项表述正确．根据文章最后一段中的．"And green roofs are more expensive…"可知绿色房顶的成本开始会很高，因此D项表述正确．而根据文章第三段中的Moreover，green roofs last two to three times longer than standard roofs可知绿色房顶的使用寿命是标准房顶的二至三倍，因此B项表述错误，根据题干要求答案选B．
61．D 推理判断题．根据文章最后一段中的．"And green roofs are more expensive，but only initially．Over time，they're cheaper once you consider their benefits energy-wise．可知Rowe对绿色房顶的未来是乐观的，因此A项错误；根据文章最后一段中的The government should not necessarily mandate（强制执行） them，but it can provide support for them，just as they do in Germany and elsewhere，可知德国政府并没有强制执行，因此B项错误；根据文章最后一段The challenges green roofs now face in the United States are something about policy and costs可知美国政府政策方面是很大的挑战，因此排除C项．根据文章第三段They can also bring in birds and butterflies，help improve biodiversity（多样性）可知绿色房顶可以给鸟类和蝴蝶提供栖息地，所以答案选D．
62．B 词义猜测题．根据文章最后一段中的And green roofs are more expensive，but only initially．Over time，they're cheaper once you consider their benefits energy-wise可知开始的时候绿色房顶会很贵，但是经过一段时间，一旦你考虑他们的益处，他们就会很便宜，由此可判断initially意思是at first"开始，首先"．at times"时常"，at present"目前，现在"，at last"最后，终于"，因此根据语境判断答案选B．
点评 考察学生的细节理解和推理判断能力，做细节理解题时一定要找到文章中的原句，和题干进行比较，再做出正确的选择．在做推理判断题不要以个人的主观想象代替文章的事实，要根据文章事实进行合乎逻辑的推理判断．
