题目内容
A regular drop in the sun’s radiation(辐射) can cause unusually cold winters in parts of North America and Europe, scientists say, a finding that could improve long-range forecasts and help countries prepare for snowstorms.
Scientists have known for a long time that the sun has an 11-year cycle during which radiation measured by sunspots on the surface reaches a peak then falls. But explaining a clear connection to weather is harder.
“Our research confirms the observed connection between solar change and regional winter climate,” lead author Sarah Ineson of the UK Met Office told the reporters in an email. The study was published in the magazine Nature Geoscience on Monday.
The researchers found that the reducing of ultraviolet(UV,紫外线) radiation from the sun can affect high-altitude wind patterns in the Northern Hemisphere(半球), causing cold winters.
“While UV levels won’t tell us what the day-to-day weather will do, they show us the bright future of improved forecasts for winter conditions for months and even years ahead. These forecasts play an important role in long-term possibility planning,” Ineson, a climate scientist, said.
Ineson and colleagues from Imperial College London and the University of Oxford used satellite data that more accurately(精确的) measures UV radiation from the sun and found a much greater change than previously thought.
They found that in years of low activity, unusually cold air forms high in the atmosphere over the tropics. This causes a redistribution(重新分配) of heat in the atmosphere, making easterly winds that bring freezing weather and snowstorms to northern Europe and the United States and milder weather to Canada and the Mediterranean.
When solar UV radiation is stronger, the opposite occurs.
More study was needed, though. A key uncertainty in the experiment lay in the satellite data used, because it covers only a few years. “So questions remain concerning both accuracy(精确) and also applicability to other solar cycles,” she said.
1.The new finding claims cold winters in the North Hemisphere can be caused by ______.
A. a sharp rise in the amount of sunspots
B. a drop in the sun’s UV radiation
C. a complex computer model simulation
D. a clear link between the sun and the earth
2. It has long been known by scientists that ______.
A. UV radiation can affect high-altitude wind patterns
B. there’s a clear connection between the sun’s activity and weather
C. the sun’s radiation reaches a peak every eleven years
D. they can predict day-to-day weather conditions from UV levels
3. What will happen if the sun turns into years of high activity according to the finding?
A. Canada and the Mediterranean will have milder weather.
B. The whole Northern Hemisphere will suffer from extreme winter days.
C. Freezing cold weather will appear in northern Europe.
D. Burning hot weather will appear in the United States.
4. It can be inferred from the passage that ______.
A. researchers have analyzed the data collected in eleven years
B. long-term weather conditions can be accurately predicted depending on UV levels
C. the research doesn’t seem correct and true enough due to limited satellite data used
D. climate scientists have just begun their research in severe weather forecast
1.B
2.C
3.D
4.C
【解析】
试题分析:科学家们发现太阳紫外线的降低会使北半球的冬天更为寒冷,这一研究发现有可能会有助于发展长期准确的天气预报,从而能够提醒人们提前防备暴风雪的来临。但是科学家们同时也指出这项研究还有待于更多的科学数据支持。
1.B细节理解题。根据文章第四段 the reducing of ultraviolet(UV,紫外线) radiation from the sun can affect high-altitude wind patterns in the Northern Hemisphere(半球), causing cold winters.可知太阳紫外线辐射的降低有可能造成北半球冬天气温的下降,所以B选项正确。
2.C细节理解题。根据文章第二段Scientists have known for a long time that the sun has an 11-year cycle during which radiation measured by sunspots on the surface reaches a peak then falls.可知太阳辐射每十一年到达一个顶峰,所以C选项正确。
3.D推理判断题。根据文章倒数第二段内容可知当太阳黑子活动减少的时候,会造成北美等地的寒冷气候,而文章倒数第三段又进一步提到When solar UV radiation is stronger, the opposite occurs.由此判断当太阳紫外线强的时候,北美等地就会炎热,故答案选D。
4.C推理判断题。根据文章末段More study was needed, though. A key uncertainty in the experiment lay in the satellite data used, because it covers only a few years.可知实验的不确定性在于可以依赖的数据较少,目前参考的仅仅是几年的数据,所以判断C为正确选项。
考点:考查科学知识类短文阅读。
It’s nearly noon on a Saturday and you can’t believe it: your teenager is still in bed, sleeping away. But before you wake him up---mumbling to yourself that you can’t believe what a lazybones he is---you should know that he probably needs all the zzzs he can get.
As much as nine hours of sleep a night, in fact. Furthermore, teens’ circadian rhythms (i.e., processes that occur once a day) mean that young people would rather stay up past midnight and rise after 9 a.m. The result? Many teens stay up late, drag themselves out of bed early for school and try to make up the sleep debt on the weekends---or in class!
“There’s a biological reason why teens stay up late and want to sleep late,” says Dr. Stan Kutcher, the Sun Life Chair of Adolescent Mental Health at Dalhousie University in Halifax. “Their natural sleep-wake cycle changes as part of the maturation process. And because of changes in their social activities, recovering from sleep debt is more problematic.”
Teens need extra sleep for several reasons. First, their brains are changing. “The brain is reorganizing itself, laying down new pathways. What we’re seeing is a relationship between brain redevelopment and an increased need for sleep,” says Kutcher. As well, growth hormones are released during sleep, so adequate sleep is crucial for adolescents’ physical development. In addition, everything adolescents have learned in school that day is being processed and locked into long-term memory during sleep. Sufficient sleep also plays a key role in overall physical health. The immune system, for example, needs deep sleep to become and remain robust(healthy).
Staying up late on school nights means that, on average, teens get between six and a half and seven hours of sleep a night---about two hours less than they need. As a result, many either doze off in class or have trouble concentrating. Some of the behavioural problems and irritability in teens can be linked directly to sleep deprivation(损失), Kutcher says.
Then there’s the breakfast issue. Dr. Carlyle Smith, a sleep researcher and a psychology professor at Trent University in Peterborough, Ont., adds that many teens simply cannot tolerate food when they first wake up, so skipping breakfast becomes another factor in reduced alertness in class. The most obvious solution to the teen sleep problem is to have school start later in the day, but initiatives(积极性) toward this across the country have gone nowhere, Smith says, mainly because of costs and resistance from school boards and teachers.
So for now, just sympathize with your teens. Encourage them to go to bed, if not early, then at least at a regular time, so they won’t develop insomnia from erratic(不稳定的) schedules. Warn them not to have too many caffeinated drinks before bed. And don’t let sleeping away the weekend become an issue to fight over. Schedule family activities to take place later in the day on weekends and let them sleep in. “If you want your kids to grow and remember stuff, let them sleep,” says Smith. “It’s not laziness. Their brains are working really, really hard.”
【小题1】The word “zzzs” (Paragraph 1) most probably means __________.
A.food | B.sleep | C.energy | D.blame |
A.Caffeinated drinks. |
B.Too much family activities. |
C.Circadian rhythms. |
D.Too much homework. |
A.Three. | B.Four. | C.Five. | D.Six. |
A.teenagers go to bed early and sleep late |
B.teenagers stay up late and get up late |
C.teenagers participate in too many social activities at night |
D.teenagers skip breakfast because of sleeping in |
A.advise parents to let sleeping teenagers lie |
B.explain why teenagers often sleep late |
C.state schools should start late in the day |
D.warn teenagers not to drink coffee before bed |
Until the 1980s, the American homeless population comprised (组成) mainly older males. Today, homelessness strikes much younger part of society. In fact, a 25-city survey by the U. S. Conference of Mayors in 1987 found that families with children make up the fastest growing part of the homeless population. Many homeless children gather in inner cities; this transient(变化无常的) and frequently frightened student population creates additional problems — both legal and educational — for already overburdened(负担过重的)urban school administrators and teachers.
Estimates of the number of homeless Americans range from 350,000 to three million. Likewise, estimates of the number of homeless school children vary radically. A U.S. Department of Education report, based on state estimates, states that there are 220,000 homeless school-age children, about a third of whom do not attend school on a regular basis, But the National Coalition for the Homeless estimates that there are at least two times as many homeless children, and that less than half of them attend school regularly.
One part of the homeless population that is particularly difficult to count consists of the “throwaway” youths who have been cast of their homes. The Elementary School Center in New York City estimates that there are 1.5 million of them, many of whom are not counted as children because they do not stay in family shelters and tend to live by themselves on the streets.
Federal law, the Stewart B. McKinney Homeless Assistance Act of 1987, includes a section that addresses the educational needs of homeless children. The educational provisions of the McKinney Act are based on the belief that all homeless children have the right to a free, appropriate education.
1. It is implied in the first paragraph that ____.
A. the writer himself is homeless, even in his eighties
B. many older homeless residents are going on strike in 25 cities
C. there is a serious shortage of academic facilities (设施).
D. homeless children are denied the opportunity of receiving free education
2. The National Coalition for the homeless believes that the number of homeless children is _____.
A. 350,000
B. 1,500,000
C. 440,000
D. 110,000
3. One part of the homeless population is difficult to estimate. The reason might well be ____.
A. the homeless children are too young to be counted as children
B. the homeless population is growing rapidly
C. the homeless children usually stay outside school
D. some homeless children are deserted by their families
4. The McKinney Act is mentioned in this passage in order to show that ___.
A. the educational problems of homeless children are being recognized
B. the estimates on homeless children are hard to determine
C. the address of grade-school children should be located
D. all homeless people are entitled(有权利的) to free education
5. The passage mainly deals with ____.
A. the legal problems of the homeless children
B. the educational problems of homeless children
C. the social status of older males
D. estimates on the homeless population