Nitrogen dioxide is a pollutant emitted by automobiles. Catalytic converters, devices designed to reduce nitrogen dioxide emissions, have been required in all new cars in Donia since 1993, and as a result, nitrogen dioxide emissions have been significantly reduced throughout most of the country. Yet although the proportion of new cars in Donia’s capital city has always been comparatively high, nitrogen dioxide emissions there have showed only an insignificant decline since 1993.
Which of the following, if true, most helps to explain the insignificant decline in nitrogen dioxide emissions in Donia’s capital city?
A. More of the cars in Donia’s capital city were made before 1993 than after 1993.
B. The number of new cars sold per year in Donia has declined slightly since 1993.
C. Pollutants other than nitrogen dioxide that are emitted by automobiles have also been significantly reduced in Donia since 1993.
D. Many Donians who own cars made before 1993 have had catalytic converters installed in their cars.
E. Most car trips in Donia’s capital city are too short for the catalytic converter to reach its effective working temperature.
虽然选择了答案是E，但是A看起来也不错啊 -- by 会员 bernadotte (2010/1/11 6:03:23)
A不对，因为题中说了新车的比例很大，但是污染没有怎么变。A说的旧车比新车多，跟这个题目中的原话差不多，没有解释任何问题。增加的新车就意味着要减少污染的，旧车比新车多，可以淘汰了一小半的旧车，换上了新车，但是污染应该也相应的减少啊。
肯定是别的原因造成的。答案E | 
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发表于 2010-1-11 06:03:23
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