科普说明文阅读理解模拟训练
本文作者： 21ST
A You can’t sleep. You’ve tried counting sheep, drinking warm milk, maybe even taking sleeping pills. Maybe next you should try cooling your brain. According to research presented Monday at Sleep 2011, the annual meeting of the Associated Professional Sleep Societies, cooling the brain can reduce the amount of time it takes people with insomnia (失眠症) to fall asleep – and increase the length of time they stay that way. To achieve “frontal cerebral (前额叶皮层) thermal transfer,” as the cooling is called, researchers Dr Eric Nofzinger and Dr Daniel Buysse of the Sleep Neuroimaging Research Program at the University of Pittsburgh School of Medicine asked 24 people – 12 with insomnia and 12 without – to wear soft plastic caps. The caps had tubes for circulating water at neutral, moderate (中等的) or maximum “cooling intensity (强度)”. The team observed how well participants slept both with and without the caps, and at the different temperature levels. Patients with insomnia who were treated at maximum cooling intensity for the whole night took about 13 minutes to fall asleep and slept 89 percent of the time they were in bed, the researchers said. This is similar to the sleep enjoyed by healthy study subjects who didn’t have insomnia, and who took 16 minutes to fall asleep and also slept 89 percent of the time. The method is effective because it slows metabolism (新陈代谢) in the frontal cortex, according to the researchers. Insomnia is associated with increased metabolism in that part of the brain; reduced metabolism apparently has the opposite effect. In a press release, Nofzinger noted that only 25 percent of patients on sleeping pills said they were satisfied with the drugs, which can cause side effects and dependence. The cooling caps may provide an effective, safe and natural alternative. “We believe this has far-reaching implications for how insomnia can be managed in the future,” he said. 1. The article is written to ______. A. analyze how insomnia affects people B. introduce a possible solution for insomnia C. teach people with insomnia how to fall asleep quickly D. promote a cooling cap among people with insomnia 2. According to the research, the “caps” could help people with insomnia ______. A. get a sounder but shorter sleep B. dream less and sleep better C. get rid of insomnia completely D. fall asleep more quickly and stay asleep for longer 3. What can be concluded from the study? A. The cooling caps didn’t have any effect on healthy participants. B. The cooler the cooling caps were, the longer it took for patients with insomnia to fall asleep. C. With the cooling caps on, patients with insomnia slept almost as well as healthy participants. D. The cooling caps help people sleep better because they increase metabolism in the frontal cortex. 4. According to the last paragraph, the cooling cap ______. A. is effective but likely to cause dependence B. has been proven safe and to have no side effects C. will be widely used to cure insomnia in the future D. is believed to pave the way for a cure for insomnia B A team led by Professor Theodore Berger, from the University of Southern California, can now manipulate (操纵) brain cells in rats so that memories stored in the hippocampus, a brain area crucial for memory formation, are activated or suppressed (抑制). It’s said that the technology could one day have medical applications. In the study, researchers first trained rats to remember which of two levers (杠杆) they pressed first, then to press the other lever. As the rats performed the task, the scientists carefully monitored the electrical activity in each creature’s hippocampus to find the pattern of nerve-cell activity involved in making a solid memory. Using the same glass needles they had used to record the nerve activity, they stimulated (刺激) nerves in the same pattern and found that the animals’ performance in the task got even better. The rats made fewer errors and were able to remember which lever was the “correct” one for a longer period of time. The scientists went a step further and suppressed the rats’ memories with a drug called MK801, which caused them to forget their task. When the animals’ brain cells were later stimulated with the “correct” pattern, they remembered again which lever to press. “What’s really exciting about this study is that when they played back the ‘good’ patterns – the patterns when the animal got the task right – it did appear to improve memory,” said Dean Buonomano, an associate professor at the University of California. The final goal, Berger said, is to help people with stroke (中风) and epilepsy (癫痫症) and the like strengthen memories and to help doctors treat them. The technology might even help sufferers of post-traumatic (创伤后) stress disorder. But first, researchers would have to show that they can stimulate or suppress far more complex memories than the ones in the rat experiment. “Here, it’s a simple task,” Buonomano said. In contrast, humans’ “memories are very rich and specific… “We have very many steps to go before this can be achieved,” he said. 5. How does “the technology” in Paragraph 1 act? A. It manipulates brain cells. B. It stores memories in the hippocampus. C. It activates memories stored in the brain. D. It suppresses memories stored in the brain. 6. In what order did the researchers conduct the rat experiment? a. Monitor the electrical activity in the rat’s hippocampi. b. Suppress the rat’s memory with a drug called MK801. c. Stimulate the rat’s nerves in the same pattern. d. Stimulate the rat’s nerves in the same pattern for a second time. e. Train the rats to remember the order of the two levers they pressed. A. a, e, b, c, d B. a, e, c, d, b C. e, a, c, d, b D. e, a, c, b, d 7. When their nerves were stimulated, the rats ______. A. forgot their task B. completed the task better C. made no errors in their task D. remembered which lever they had pressed for a shorter time 8. Which of the following statements is TRUE according to the article? A. MK801 is a drug that can be used to stimulate nerves. B. The study is expected to be used to help stoke and epilepsy patients recover completely. C. There is still a long way to go before the study can be used to improve humans’ memories. D. Researchers have studied far more complex memories than the ones in the rat experiment. C Striking new images from the mountains of Mars may be the best evidence yet of the existence of flowing liquid water on the planet, the essential ingredient for life. The findings, reported recently in the journal Science, come from a joint US-Swiss study. A series of images from the Mars Reconnaissance Orbiter show many long, dark trails a few meters wide. They start to appear between rocky outcrops (露出部分) and flow hundreds of meters down sharp slopes toward the plains below. They spread on hillsides warmed by the summer sun, flow around obstacles (障碍物), but when winter returns, the trails fade away. This suggests that they are made of thawing (融化的) mud, say researchers. “It’s hard to imagine they are formed by anything other than fluid seeping (渗漏) down slopes,” said Mars Reconnaissance Orbiter Project Scientist Richard Zurek. But, he continued, they appear when it’s still too cold for fresh water. The best explanation for these observations was “flow of salty water”, said lead author Professor Alfred McEwen from University of Arizona, US. The presence of salt lowers the temperature at which water freezes, and water about as salty as the Earth’s oceans could exist at these sites in summer. The findings are important for the search for life outside the Earth and its atmosphere. Liquid water is absolutely essential for life, and scientists have found life on Earth in almost all moist (潮湿的) places. “So perhaps there could be hardy (耐寒的) microbes (微生物) surviving in these short periods of summer meltwater (融化的水) on the desert surface of Mars,” said Lewis Dartnell from University College London, who was not involved in the study. Expert on life in extreme environments, Professor Shiladitya DasSarma of the University of Maryland, also not involved in this study agreed that this was the case. “Their results are consistent with the presence of many large underground salty lakes on Mars,” he said. “The study opens the possibility that these kinds of salt-loving microbes may also exist our neighboring planet,” he continued. According to scientists, these microbes are champions at putting up with the most punishing conditions, complete dryness and ionizing (电离的) radiation. 9. What would be the best title for the text? A. Interesting facts about Mars B. Signs of flowing water on Mars C. Salt-loving microbes found on Mars D. Underground salty lakes uncovered on Mars 10. According to the researchers, the trails on Mars _____. A. can be only seen in summer B. are wide and light-colored C. are probably formed by thawing mud D. mostly appear on the plains below sharp slopes 11. Why does Professor Alfred McEwen suppose the meltwater on Mars to be salty? A. Because saltiness lowers the freezing temperature of water. B. Because salt-loving microbes were discovered in the water. C. Because the water has proved to be as salty as the Earth’s oceans. D. Because there are many large underground salty lakes on Mars. 12. The underlined word “this” in the last paragraph but one refers to _____. A. the existence of meltwater on Mars B. the extreme environments on Mars C. the possibility of microbial life on Mars D. the fact that life exists in almost every moist place on Earth D Myopia, or nearsightedness, is on the increase in most places, but in countries such as Singapore it has reached extraordinary levels. There, 80 percent of 18-year-old male army recruits are myopic, up from 25 percent just 30 years ago. Employers such as the police are having problems finding people who meet their requirements. Questions have been raised as to why the rate of myopia is so much higher in East Asia than elsewhere. The conventional view is that people from the region have genetic variations (变异) that make them more susceptible (易感染的). But after reviewing over 40 studies, Morgan and Kathryn Rose, researchers from the University of Sydney, argue that there is no evidence to support this. They use several lines of evidence to debunk the idea that genes can explain the Asian epidemics (流行病). For instance, 70 percent of 18-year-old men of Indian origin living in Singapore have myopia, while in India itself the rate is roughly 10 percent. “The simplest explanation is that you have a massive environmental effect that is swamping (压倒) out the genetic influence,” says Morgan. In other words, given the wrong lifestyle, everyone is susceptible to myopia. And it looks as if those lifestyle changes are beginning to be felt in some western countries too. In Sweden, for instance, 50 percent of children aged 12 now have myopia. It is expected that when these children reach 18 the rate will be more than 70 percent. “It is an impressive piece of work,” says a scientist of Ohio State University. But if the increase really is due to too much reading, she points out, then lenses that eliminate the stress of focusing on near work should help stop myopia getting any worse. In fact, studies show the lenses are of little help. This could be because we have not identified all the lifestyle factors involved, including ones that protect against myopia, says Morgan. For example, children who read less also tend to spend more time outdoors, where better light may reduce the need to focus precisely for near vision. Studies show that children who play sport are less susceptible to myopia. Some researchers have even proposed that diet is one of the factors contributing to the rise in myopia. They argue that eating too much refined starch (淀粉) affects the growth of the eyeball. 13. What is the text mainly about? A. Why Singapore is facing a myopia epidemic. B. How to protect your eyes from myopia. C. What is causing the rise in myopia in East Asia. D. What kind of people are more susceptible to myopia. 14. The underlined word “debunk” in Paragraph 2 probably means ________. A. convince people of (something) B. show the falseness of (something) C. sum up D. put forward 15. Comparing the myopia rate in people of Indian origin living in Singapore and Indian natives, Morgan intends to prove that _______. A. genetic variations are leading to the Asian myopia epidemic B. India has a much lower rate of myopia than Singapore C. Indians are easily affected by environmental changes D. Lifestyle changes are behind the high rate of myopia 16. Which of the following is TRUE according to the article? A. The rate of myopia is expected to go down in some western countries. B. It has been proven that lenses can help prevent myopia getting worse. C. Playing sports helps children lower their chances of getting myopia. D. Eating refined starch could help protect against myopia. E Drownings, bicycle injuries, falls, and pedestrian (步行) accidents are the most common causes of childhood injury or death. Here’s what you need to know to avoid tragedy: Drowning: Each year, thousands of children die from drowning, with two-thirds of accidents occurring in the summer. To protect kids, parents should install (安装) multiple layers of protective devices (装置), with each layer offering another opportunity to avoid a tragedy. Fences, door alarms, pool alarms and pool covers are all somewhat effective individually, but their effectiveness is increased dramatically when used in combination with one another. Falls: Falls from heights kill 140 children under the age of 15 each year in the United States, and seriously injure three million more, making falls the leading cause of non-deadly injury for this age group. According to the American Academy of Pediatrics (AAP), falls are especially a problem for children living in multi-story housing during the summer months, when windows are open and children are more likely to be playing on fire escapes, roofs and balconies. To keep kids safe, AAP recommends window guards be installed on second story and higher windows. When choosing guards, install those that are operable in the event of emergencies like a house fire. Using childproof gates can prevent falls down stairways. Nevertheless, no gate can replace parental supervision (监督). Bikes: Bikes accidents kill over 1,500 children aged 14 and under each year. Of these deaths, more than half occurred during the summer. According to the AAP, head injuries from cycling are the most common cause of death (70 percent to 80 percent of cases) and the leading cause of disability. A recent study in Seattle, Washington showed that helmets reduced the risk of head injury by 85 percent and brain injury by 88 percent. When purchasing a bike helmet, parents are urged to make sure it meets the bicycle helmet safety standards of the American National Standards Institute (ANSI). Pedestrian: Over 6,000 kids aged 14 and under die every year as a result of an unintentional pedestrian-related injury. As a general rule, kids under 10 should not be crossing the street alone. Young children lack the ability to judge the speed and distance of oncoming traffic. Parents need be models and teach proper pedestrian behavior. Cross at the corner and when you do cross, continue to look both ways because there are likely to be more cars turning into your path or people speeding. Obey all the traffic signals. 17. What is the point of the article? A. To introduce factors that cause risks for children. B. To explain why summer is a risky time for kids. C. To give tips on how to keep kids safe in summer. D. To describe what to do to prevent accidents at home. 18. To protect kids against falls, families living in multi-story housing should _____ according to the AAP. A. never leave windows open when children are left alone at home B. tell kids not to play on balconies, roofs and fire escapes C. teach kids to use childproof gates in the event of emergencies D. install window guards on second story and higher windows 19. When riding a bicycle, you should ______ according to the AAP. A. wear a proper helmet B. avoid riding at night C. not take anyone in the back seat D. not ride on the streets under the age of 14 20. What can be concluded from the article? A. Bicycles cause the most non-deadly injuries for children in the US each year. B. Pedestrian accidents happen much more frequently than drownings in America each year. C. A combination of fences, door alarms and pool covers can greatly reduce the risks of drownings. D. Children should never be allowed to cross the street on their own. （答案见A32版） |  |
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