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【单选题】
Green Power Youve insulated the attic, installed triple-glazed windows, and bought high-efficiency appliances. Can you make your home any more eco-friendly? For an increasing number of Americans, the answer is yes. You can let nature help cut your utility bill. It may be as simple as replacing outdoor lights with solar-powered fixtures or signing up for your utilitys 'green power' program. Thanks to rapid improving technology and government subsidies, thousands of Americans living in remote locations are finding it can be cheaper to use the sun and wind than fossil fuels. However, dont cut your ties to the local utility just yet. (A)While renewable energy wont replace coal and natural gas soon (or ever, critics contend), consumers have more choices in their energy mix than ever before. (B)And theyre not at all whole-bran environmentalists: Roldan Montalvo runs a gas station here in Hebbronville, Texas. (C)But when he wanted to bring electricity to his cabin eight miles out of town, he went solar. The reason was simple. The utility company wanted $100000 to extend its electric line to his cabin. (D)Mr. Montalvo paid less than $8000 for his solar system, 'Its all right so far,' he says, looking up at the three solar panels that run a few lights, a fan, and a TV inside. 'I can run power tools.' Others, of course, take a more enthusiastic line. 'There is a new focus on renewable.' says Thomas White, chairman and chief executive of Enron Renewable Energy Corporation, which has completed the worlds largest wind farm in Minnesota. 'My feeling is that we are at the point in time where the personal computer was in the late 70s,' adds Mac Moore, Director of Business Development for BP Solar, one of the largest manufacturers and marketers of solar electric systems in the world. 'Over the next 10 years, if things go well, theres going to be a revolutionary change in the way that we obtain power.' Wind power represents an even more compelling argument for remote homeowners. Turbines have become so much more efficient over the past decades that homeowners a quarter mile from a utility line may find it cheaper to put up a wind turbine than to pay the utility to extend its service. But for most consumers, barriers remain. For one thing, renewable energy systems are expensive to install and require more than a decade before consumers see a payback. Even a good deal on solar panels in a high-sun area would still cost a typical homeowner 30 cents a kilowatt hour, explains the CEO of Strategy Unlimited, a technology-research firm in Mountain View, Calif. Thats far above the 6 to 15 cents that Americans typically pay their local utility, he adds. Small-scale wind turbines are much more competitive—anywhere from 8 to 15 cents a kilowatt-hour, says Mike Bergey, President of Bergey Windpower in Norman, Oklahoma. But they still require a $30000 to $35000 investment up front and it would take most homeowners 15 to 20 years before theyd see any payback. There are other drawbacks. Since these systems only produce energy intermittently, theres no guarantee homeowners can store enough energy to run their homes when the sun isnt shining or the wind isnt blowing. Then theres aesthetics. Will the neighbor accept those solar panels on your roof? Do you want a 100-foot-high wind turbine humming in your backyard like a muffled helicopter? Thats why companies like Bergey Windpower are targeting rural residents in the United States—especially those in states such as California, where the government will pay up to half the cost of installing renewable-energy systems. The word insulate in Paragraph 1 is closest in meaning to ______.
A.
separate
B.
decorate
C.
install
D.
expand
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参考答案:
举一反三
【单选题】极大似然估计的基本思想是【 】。
A.
用使样本出现可能性最大的参数作为总体参数的估计
B.
用样本矩代替总体矩
C.
用总体矩代替样本矩
D.
用出现可能性最大的样本参数作为总体参数的估计
【判断题】任意两个函数 都可以复合成复合函数
A.
正确
B.
错误
【判断题】矩估计法的基本思想是用样本矩估计总体矩。
A.
正确
B.
错误
【判断题】矩法估计的基本思想是用样本矩估计总体矩,用样本矩的函数估计总体矩的函数。A. 对 B. 错
A.
正确
B.
错误
【判断题】任意两个函数都可以复合成一个复合函数
A.
正确
B.
错误
【单选题】(单选题)“导游小李在带团过程中,发现游客张某的言行违反了当地的法律与风俗习惯,小李及时制止了张某的言行,小李行使了导游的( )权利。
A.
人身权
B.
履行职务权
C.
申请复议权书
D.
诉权
【简答题】小学阶段是发展学生个性( )。
【判断题】函数 , 可以复合成函数
A.
正确
B.
错误
【单选题】小学阶段是发展学生个性
A.
并不重要的时期
B.
非常重要的奠基时期
C.
.没有效果的时期
D.
最不会受外界影响的时期
【判断题】任意两个函数都可以复合成一个复合函数 .
A.
正确
B.
错误
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