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  3. If two scientists at Los Alamos National Laboratory are correct, people will still be driving gasoline-powered cars 50 years fro

If two scientists at Los Alamos National Laboratory are correct, people will still be driving gasoline-powered cars 50 years fro

admin2012-02-29  48
问题     If two scientists at Los Alamos National Laboratory are correct, people will still be driving gasoline-powered cars 50 years from now, giving out heat-trapping carbon dioxide into the atmosphere — and yet that carbon dioxide will not contribute to global warming.
    The scientists, F. Jeffrey Martin and William L. Kubic Jr., are proposing a concept, which they have named Green Freedom, for removing carbon dioxide from the air and turning it back into gasoline.
    The idea is simple. Air would be blown over a liquid solution which would absorb the carbon dioxide. The carbon dioxide would then be extracted (提取) and subjected to chemical reactions that would turn it into fuel.
    Although they have not yet built a synthetic fuel factory, or even a small prototype (原型), the scientists say it is all based on existing technology.
    "Everything in the concept has been built, is operating or has a close cousin that is operating," Dr. Martin said.
    The Los Alamos proposal does not violate any laws of physics, and other scientists have independently suggested similar ideas.
    In the efforts to reduce humanity’s emissions of carbon dioxide, three solutions have been offered: hydrogen(氢-)-powered fuel cells, electric cars and biofuels. Biofuels are gasoline substitutes produced from plants like corn or sugar cane. Plants absorb carbon dioxide as they grow, but growing crops for fuel takes up wide strips of land.
    Hydrogen-powered cars emit no carbon dioxide, but producing hydrogen requires copious (大量的) energy, and if that energy comes from coal-fired power plants, then the problem has not been solved.
    Electric cars also push the carbon dioxide problem to the power plant. And electric cars have typically been limited to a range of tens of miles as opposed to the hundreds of miles that can be driven on a tank of gas.
    Gasoline, it turns out, is an almost ideal fuel (except that it produces CO2). If it can be made out of carbon dioxide in the air, the Los Alamos concept may mean there is little reason to switch, after all.
    "It’s definitely worth pursuing," said Martin I. Hoffert, a professor of physics at New York University. Other scientists also said the proposal looked promising but could not evaluate it fully because the details had not been published.
The biggest problem with hydrogen-powered cars is that______.
选项 A、there is no cheap source of hydrogen energy
B、they may still be a cause of global warming
C、safety problems might occur in hydrogen production
D、they are not suitable for long-distance travel
答案B
解析 根据题干中的hydrogen-powered cars将本题出处定位到第八段。该段提到，氢气动力汽车不排放二氧化碳，但是制造氢气需要大量能量，且如果这种能量来源于火力发电厂，那么，问题还是不能得到解决。由此可知，如果制造氢气需要的能量来源于排放二氧化碳的火力发电厂，那么氢气动力汽车还是会造成全球变暖，故答案为[B]。其余三项在文中未提及。
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