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With the world’s population estimated to grow from six to nine billion by 2050, researchers, businesses and governments are already dealing with the impact this increase will have on everything from food and water to infrastructure (基础设施) and jobs. Underlying all this (1) will be the demand for energy, which is expected to double over the next 40 years.Finding the resources to meet this demand in a (2) sustainable way is the cornerstone (基石) of our nation’s energy security, and will be one of the major (3) of the 21st century. Alternative forms of energy—bio-fuels, wind and solar, to name a few—are 4 being funded and developed, and will play a growing (5) in the world’s energy supply. But experts say that, even when (6) , alternative energy sources will likely meet only about 30% of the world’s energy needs by 2050.For example, even with (7) investments, such as the ＄93 million for wind energy development (8) in the American Recovery and Reinvestment Act, important alternative energy sources such as wind and bio-fuels (9) only about 1% of the market today.Energy and sustainability experts say the answer to our future energy needs will likely come from a lot of (10) —both traditional and alternative.A．stableB．solutionsC．significantD．roleE．progressF．marvelousG．includedH．growthI．exactlyJ．consistK．compriseL．competitionsM．combinedN．challengesO．certainly （10）处应填（）

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The popular notion that older people need less sleep than younger adults is a myth, scientists said yesterday.While elderly people (1) to sleep for fewer hours than they did when they were younger, this has a(n) (2) effect on their brain’s performance and they would benefit from getting more, according to research.Sean Drummond, a psychiatrist (心理医生) at the University of California, San Diego, said that older people are more likely to suffer from broken sleep, while younger people are better at sleeping (3) straight through the night.More sleep in old age, however, is (4) with better health, and most older people would feel better and more (5) if they slept for longer periods, he said."The ability to sleep in one chunk (整块时间) overnight goes down as we age but the amount of sleep we need to (6) well does not change," Dr Drummond told the American Association for the Advancement of Science conference in San Diego."It’s (7) a myth that older people need less sleep. The more healthy an older adult is, the more they sleep like they did when they were (8) . Our data suggests that older adults would benefit from (9) to get as much sleep as they did in their 30s. That’s (10) from person to person, but the amount of sleep we had at 35 is probably the same amount as we need at 75."A．alertB．associateC．attractingD．clingE．continuingF．definitelyG．differentH．efficientlyI．formallyJ．functionK．mixedL．negativeM．sufficientN．tendO．younger （9）处应填（）

When we think of green buildings, we tend to think of new ones—the kind of high-tech, solar-paneled masterpieces that make the covers of architecture magazines. But the U.S. has more than 100 million existing homes, and it would be (1) wasteful to tear them all down and (2) them with greener versions. An enormous amount of energy and resources went into the construction of those houses. And it would take an average of 65 years for the (3) carbon emissions from a new energy-efficient home to make up for the resources lost by destroying an old one. So in the broadest (4) , the greenest home is the one that has already been built. But at the same time, nearly half of U.S. carbon emissions come from heating, cooling and (5) our homes, offices and other buildings. "You can’t deal with climate change without dealing with existing buildings," says Richard Moe, the president of the National Trust.With some (6) , the oldest homes tend to be the least energy-efficient. Houses built before 1939 use about 50% more energy per square foot than those built after 2000, mainly due to the tiny cracks and gaps that (7) over time and let in more outside air.Fortunately, there are a (8) number of relatively simple changes that can green older homes, from (9) ones like Lincoln’s Cottage to your own postwar home. And efficiency upgrades (升级) can save more than just the earth; they can help (10) property owners from rising power costs.A．accommodationsB．clumsyC．doubtfulD．exceptionsE．expandF．historicG．incrediblyH．poweringI．protectJ．reducedK．replaceL．senseM．shiftedN．supplyingO．vast （7）处应填（）

设int a=5，b=6，表达式(++a= =b--) ++a：--b的值是【7】。

The popular notion that older people need less sleep than younger adults is a myth, scientists said yesterday.While elderly people (1) to sleep for fewer hours than they did when they were younger, this has a(n) (2) effect on their brain’s performance and they would benefit from getting more, according to research.Sean Drummond, a psychiatrist (心理医生) at the University of California, San Diego, said that older people are more likely to suffer from broken sleep, while younger people are better at sleeping (3) straight through the night.More sleep in old age, however, is (4) with better health, and most older people would feel better and more (5) if they slept for longer periods, he said."The ability to sleep in one chunk (整块时间) overnight goes down as we age but the amount of sleep we need to (6) well does not change," Dr Drummond told the American Association for the Advancement of Science conference in San Diego."It’s (7) a myth that older people need less sleep. The more healthy an older adult is, the more they sleep like they did when they were (8) . Our data suggests that older adults would benefit from (9) to get as much sleep as they did in their 30s. That’s (10) from person to person, but the amount of sleep we had at 35 is probably the same amount as we need at 75."A．alertB．associateC．attractingD．clingE．continuingF．definitelyG．differentH．efficientlyI．formallyJ．functionK．mixedL．negativeM．sufficientN．tendO．younger （8）处应填（）