新prep1-104~

xiaoxiangxixi

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.

选E，请问A哪里错了？题干说1993年后生产的汽车都要装Catalytic converters，A说首都大部分车是93年以前造的，也就是没有Catalytic converters啊，所以解释了废气降低的insignificant啊~

linglingdan

这个要看题目的最后一句：

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.

这句话很明白的一个转折已经把lz你的推断给堵死了。comparatively high显然是跟全国平均水平相比，而new cars是肯定装了那个设备的。

A选项传递了一个信息：老车比新车多。但是从文章的意思可以看出：这个capital city里即使老车比新车多，新车占的比例还是比全国平均要高的。而全国范围的nitrogen dioxide emission已经明显下降，按这个逻辑capital city没理由不下降。所以这个选项对推翻或者支持论点都没有帮助。

xiaoaojiang

D为什么不对？
以前的也都装了，所以就不会有太大变化啊？

linglingdan

D为什么不对？
以前的也都装了，所以就不会有太大变化啊？
xiaoaojiang 发表于 2010-5-8 08:23

  D的问题是根本没提到capital city，是个全国范围的考虑。而题目中已经有了全国范围内的排放大大下降，导致这个选项的证据没有力度。

xiaoaojiang

明白了，感谢~