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  3. When George W. Bush delivered his State of the Union Address this past January, three words appeared that had not previously bee

When George W. Bush delivered his State of the Union Address this past January, three words appeared that had not previously bee

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问题    When George W. Bush delivered his State of the Union Address this past January, three words appeared that had not previously been heard from the Oval Office: Switchgrass, stalks and woodchips.
    Bush’s signals on renewable energy have been decidedly mixed. Shortly before he visited the National Renewable Energy Laboratory (NREL) in Colorado last February, a $5 million funding shortfall forced the lab to lay off 32 workers. Bush blamed the layoffs, and NREL got its funding back.
    Switchgrass is a fast-growing perennial plant native to the central and eastern U.S. and tolerant of many different soil types. To make cellulosic ethanol, switchgrass -- or any cellulose-based plant -- is broken down to make sugar, then fermented to make the fuel. Supporters say that when blended with petroleum products, ethanol from switchgrass results in a net energy gain of 334 percent, compared to just 21 percent for corn- based ethanol.
    The cellulosic process has been invented and is being refined, but it hasn’t been commercialized, and that’ s what is preventing it from going into our tanks today, says former CIA Director James Woolsey, among switchgrass’ s biggest supporters.
Corn-based ethanol has made great strides. According to Tom Slunecka, executive director of the Ethanol Promotion and Information Council, the U.S. currently produces four billion gallons a year, or approximately three to four percent of the fuel supply. "It’ s growing rapidly," he says. "By 2012 we’ re projecting 7.5 billion gallons, but I think we’ 11 far surpass that." Automakers get federal tax credits for producing "bi-fuel" cars and trucks that can nm on ethanol, but until recently the lack of an ethanol refueling infrastructure (永久性设施) obstructed the actual use of the fuel. But now General Motors and other carmakers are promoting ethaonol vehicles with a new vigor. Even without bi-fuel technology, all cars today can burn a 10 percent ethanol blend
Slunecka says biobased ethanol production is still in its infancy: He cites a Canadian plant currenty producing 100,000 gallons per year. "It works, it’ s not science down the road," he says. "Private companies m trying to crack the cost barrier. But the feedstock potential is enormous. I can’ t wait until these cellulosic plants are bolted onto the front side of traditional ethanol plants."
    David Bransby, a professor in Auburn University’ s Agronomy Department, says we need to take action because we’ re in an international competition. "Europe is ahead of everybody in the use of biodiesel, and Brazil! is leading the world in the production and use of ethanol. We are behind. I hope that the President’ s address indicates that there is going to be a change, but he’ s fighting a war in Iraq and trying to recover from two, hurricanes. To be quite honest, these alternative fuels are just as important as those other things. It’s all part o national security and needs to be treated with the same priority."
The passage implies that______.
选项 A、switchgrass is the most ideal raw material for the cellulosic ethanol production
B、corn-based ethanol has higher energy rate than switchgrass-based ethanol
C、corn-based ethanol has been invented and is being refined, but not commericalized
D、switchgrass is directly used as raw material for the cellulosic ethanol production
答案A
解析 本题主要考查对第三。四、五段的正确理解。我们建议用排除法，根据第三段最后一句(ethanol from switchgrass results in a net energy gain of 334 percent, compared to just 21 percent for com-based ethan01 ，我们可判断B 项说法不正确，根据第五段(以玉米为原料基础生产的酒精年产量已达40亿加仑，约占燃料供应总量的3-4％．而且产量还呈现增长势头。 和第四段(纤维质植物的处理加工还没有进行商业化运
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