作者：英吉
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.
题目分析：A说93年前和93年后什么时候建造的车更多，没提过，杀。B说新车数量减少，没提，杀.C说除了nd之外的污染物，原文反复问绕的就是用什么方法减少nd的排放，这个选项范围驴唇不对马嘴，杀。D说93年前的车已经装了cc了，但是文章围绕的是93年之后的事情谈的，时间上毫无交集，杀.E说这个城市的距离太短了从而使CC无法达到有效工作温度，这个选项就是说CC不好使，cc不好使了nd的含量自然降不下来，选这个！
