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25. There should be a greater use of gasohol. Gasohol is a mixture of alcohol and gasoline, and has a higher octane rating and fewer carbon monoxide emissions than straight gasoline. Burning gasohol adds no more carbon dioxide to the atmosphere than plants remove by photosynthesis.

B. Since less gasoline is needed with the use of gasohol, an energy shortage is less likely.

C. Cars burn on the average slightly more gasohol per kilometer than they do gasoline.

D. Gasohol is cheaper to produce and hence costs less at the pump than gasoline.

E. Burning gasoline adds more carbon dioxide to the atmosphere than plants can remove.

答案为C，但为什么E不对？原文说燃烧gasohol产生的二氧化碳不比植物光合作用消耗的多，E则说燃烧Gasohol产生的二氧化碳比植物消耗的多，那就已经contradict原文了，也就削弱了！

以下是引用jimoshanlin在2008-6-27 14:40:00的发言：

Each of the following, if true, strengthens the argument above EXCEPT:

A. Cars run less well on gasoline than they do on gasohol.

B. Since less gasoline is needed with the use of gasohol, an energy shortage is less likely.

C. Cars burn on the average slightly more gasohol per kilometer than they do gasoline.

D. Gasohol is cheaper to produce and hence costs less at the pump than gasoline.

E. Burning gasoline adds more carbon dioxide to the atmosphere than plants can remove.

请高人指点下

E是加强文章的。E说燃烧gasoline所增加的二氧化碳比植物能吸收的多。也就是说燃烧gasoline会导致CO2留在大气，无法被吸收。显然直接就加强了文章的结论。