再求教PREP逻辑一道

zhaoyiqing

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.

我选的是D呢
求教

zhaoyiqing

谢谢LS
已经明白了

xhaek

你可能在理解D选项上有偏差
我觉得D选项是说那些购买1993年以前产的汽车的D城市民已经都装了减排装置了。这个意思里没有说他们装减排装置是在1993年以前吧？只是说那些1993年以前产的汽车都已经装了减排，这个安装大部分肯定是在1993年以后安装的，因为在1993年才开始要求新车装减排。
那么E选项取反，就是说D城里的汽车跑的路程足够长，减排装置可以达到一个高效的工作温度，那么，就无法解释为什么减排效果仍然不明显。
所以我觉得E才是最佳的解释原因
个人愚见，多指教

zhaoyiqing

对啊 但我觉得D也很对啊 很多都有装了 那再加一个条令就起不到效果了啊

xiaoxingyao

选D的逻辑不是恰好相反嘛，如果旧车都装了装置的话，Nitrogen应该是会显著下降的啊，
E正好的，由于路程太短，导致装置没有发挥足够的作用，所以Nitrogen不会显著的下降的啊

JayNicholas

答案是E   意思是路程太短 不能达到工作温度  所以导致了  减排效果不好