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.
問個想不透的問題 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.
1993 安裝後...有短暫的滅少...
那搭配E .. 又說 too short for the catalytic converter to reach its effective
感覺二句中有矛盾...一個是有安裝後有減少...E是 trip is too short以致於沒減少 (最大疑問在這裡)
throughout most of the country....整個country 降低......而非單指D城. 如果是這原因,我就了解了
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发表于 2010-3-24 00:20:53
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