GWD-5-38

38. 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?

1. More of the cars in Donia’s capital city were made before 1993 than after 1993.


2. The number of new cars sold per year in Donia has declined slightly since 1993.


3. Pollutants other than nitrogen dioxide that are emitted by automobiles have also been significantly reduced in Donia since 1993.


4. Many Donians who own cars made before 1993 have had catalytic converters installed in their cars.


5. Most car trips in Donia’s capital city are too short for the catalytic converter to reach its effective working temperature.

The answer is E.  But can someone tell me why not A?

I think A{More of the cars in Donia’s capital city were made before 1993 than after 1993} violates the premise {the proportion of new cars in Donia’s capital city has always been comparatively high}, so how does it help to explain the insignificant decline in nitrogen dioxide emissions in Donia’s capital city?

个人意见。呵呵,请各位指点

为什么我的答案是D？

E否定了catalytic converter 的作用，与题干insignificant decline 不符合。D说明原来的排放级别就低，当然减少的程度也就小。

philikittist MM, thanks

请教这个题目的意思

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.

红线部分前面的是假设，后面的是实际结果？我怎么看不出来呀。。。

and as a result, nitrogen dioxide emissions have been significantly reduced throughout most of the country.

这句是全国范围内的结果.

nitrogen dioxide emissions there have showed only an insignificant decline since 1993.

这句是首都的结果.

两者之间有差异, 题目要求给出一个解释. E explains it.

E对，没问题，还是想再把A讨论清楚。

A. More of the cars in Donia’s capital city were made before 1993 than after 1993.

如果把这里所说的cars理解为那些新车，

这样理解的话，就算是Catalytic converters在全国普及开了，但在Donia’s capital，因为新车是made before 1993, 所以不用安装Catalytic converters。也是能说明an insignificant decline since 1993。

还请大家指点。