职称英语理工类考试辅导：完形填空biofuels
Ausubel of Rockefeller University in New York， US. says the key renewable energy sources， including sun， wind and biofuels， would all require vast 1 of land if developed up to large scale production1 – unlike nuclear power. That land would be far better left alone2， he says. Renewables look attractive when they are quite 2 。 But if we start producing renewable energy on a large scale， the fallout is going to be horrible. Instead， Ausubel argues 3 renewed development of nuclear.
Ausubel draws his conclusions by analysing the amount of energy renewables， natural gas and nuclear can produce in terms of power per square metre of land used3. Moreover， he claims that as renewable energy use increases， this measure of efficiency4 will 4 as the best land for wind， biofuels， and solar power gets used up.
Using biofuels to obtain the 5 amount of energy as a 1000 megawatt nuclear power plant would require 2500 square kilometres of farm 6 ， Ausubel says. "We should be sparing land for nature5， not using it as pasture for cars and trucks，" he adds.
Solar power is much more efficient than biofuel in terms of the area of land 7 ， but it would still require 150 square kilometres of photovoltaic cells to 8 the energy production of the 1000 MW nuclear plant. In another example， he says meeting the 2005 US electricity demand via wind power alone would need 780，000 square kilometres， an area the size of Texas.
However， several experts are highly critical 9 Ausubel’s conclusions. John Turner of the US government’s National Renewable Energy Laboratory says that 10 the US got all of its power from solar energy， it would still need less than half the amount of land that has been paved over for highways. Further， it need not 11 additional land. The US could get a quarter of its energy just from covering rooftops of 12 buildings， he says.
According to Turner， the same "dual use" also applies to wind power6. "The footprint for wind7 is only 5% of the land that it 13 。 Farmers can still farm the land that the turbines are on8. Turner says looking solely at land use is an oversimplification of the 14 。 "I’m not sure I’d want to build one of these nuclear plants in Afghanistan9， but we could 15 put in wind and solar power，" he adds.
词汇：
renewable adj. 可再生的
n. 可再生能源 photovoltaic adj. 光电的
rooftop n. 屋顶
biofuel n 生物燃料 footprint n. 足迹，影响区域
fallout n. 余波，结果 turbine n. 涡轮机
megawatt n. 兆瓦
pasture n. 牧场，牧地 Oversimplification n. 过于简单化
注释：
1. if developed up to large scale production：如果开发达到大规模的程度。 if developed up to large scale production ＝ if (the key renewable energy sources were) developed up to large scale production
2.That land would be far better left alone：保留那一片土地远比使用它为好。(be) left alone 是“别动它”的意思。如：
Leave him alone. He can solve the problem himself.
(不要打搅他。他自己会解决问题的。)