标题: prep08一道题求助！！ [打印本页] 作者: 小陈冲鸭 时间: 2018-11-30 23:15 标题: prep08一道题求助！！ 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.
作者: newyork201999 时间: 2018-12-1 00:49
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.
这里已经说comparatively high 了
A 根本不是问题 .. 而且很正常。 降低污染的关键是变化，本来100%的旧车，很多被新车代替，哪怕20%、30% ，也应该有效果。况且上面已经说了和其他地方比都属于比较高了，而全国整体范围内污染都显著减轻，可为什么这里没有呢