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标题: GWD 5-Q38 [打印本页]

作者: lainemai 时间: 2014-9-19 22:35
标题: GWD 5-Q38

Nitrogendioxide is a pollutant emitted by automobiles. Catalytic converters, devicesdesigned to reduce nitrogen dioxide emissions, have been required in all newcars in Donia since 1993, and as a result, nitrogen dioxide emissions have beensignificantly reduced throughout most of the country. Yet although the proportionof new cars in Donia's capital city has always been comparatively high,nitrogen dioxide emissions there have showed only an insignificant declinesince 1993.

Which of thefollowing, if true, most helps to explain the insignificant decline in nitrogendioxide emissions in Donia's capital city?

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

B. The number of new cars sold per year in Donia has declinedslightly since 1993.

C. Pollutants other than nitrogen dioxide that are emitted byautomobiles have also been significantly reduced in Donia since 1993.

D. Many Donians who own cars made before 1993 have had catalyticconverters installed in their cars.

E. Most car trips in Donia's capital city are too short for thecatalytic converter to reach its effective working temperature.

求解A为什么不对

作者: lainemai 时间: 2014-9-20 08:58
没有人回答只好自己顶上去了

求大牛解答

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