1、大学英语六级改革适用（阅读）模拟试卷 75及答案与解析 Section B 0 Graying Population Stays in the Pink A)Elderly people are growing healthier, happier and more independent, say American scientists. The results of a 14-year study to be announced later this month reveal that the diseases associated with old age are afflicting
2、fewer and fewer people and when they do strike, it is much later in life. B)In the last 14 years, the National Long-term Health Care Survey has gathered data on the health and lifestyles of more than 20,000 men and women over 65. Researchers, now analysing the results of data gathered in 1994, say a
3、rthritis, high blood pressure and circulation problems the major medical complaints in this age group are troubling a smaller proportion every year. And the data confirms that the rate at which these diseases are declining continues to accelerate. Other diseases of old age dementia, stroke, arterios
4、clerosis and emphysema are also troubling fewer and fewer people. C)“It really raises the question of what should he considered normal ageing“, says Kenneth Manton, a demographer from Duke University in North Carolina. He says the problems doctors accepted as normal in a 65-year-old in 1982 are ofte
5、n not appearing until people are 70 or 75. D)Clearly, certain diseases are beating a retreat in the face of medical advances. But there may be other contributing factors. Improvements in childhood nutrition in the first quarter of the twentieth century, for example, gave todays elderly people a bett
6、er start in life than their predecessors. E)On the downside, the data also reveals failures in public health that have caused surges in some illnesses. An increase in some cancers and bronchitis may reflect changing smoking habits and poorer air quality, say the researchers. “These may be subtle inf
7、luences“, says Manton, “but our subjects have been exposed to worse and worse pollution for over 60 years. It s not surprising we see some effect“. F)One interesting correlation Manton uncovered is that better-educated people are likely to live longer. For example, 65-year-old women with fewer than
8、eight years of schooling are expected, on average, to live to 82. Those who continued their education live an extra seven years. Although some of this can be attributed to a higher income, Manton believes it is mainly because educated people seek more medical attention. G)The survey also assessed ho
9、w independent people over 65 were, and again found a striking trend. Almost 80% of those in the 1994 survey could complete everyday activities ranging from eating and dressing unaided to complex tasks such as cooking and managing their finances. H)That represents a significant drop in the number of
10、disabled old people in the population. If the trends apparent in the United States 14 years ago had continued, researchers calculate there would be an additional one million disabled elderly people in today s population. According to Manton, slowing the trend has saved the United States governments
11、Medicare system more than $200 billion, suggesting that the greying of America s population may prove less of a financial burden than expected. I)The increasing self-reliance of many elderly people is probably linked to a massive increase in the use of simple home medical aids. For instance, the use
12、 of raised toilet seats has more than doubled since the start of the study, and the use of bath seats has grown by more than 50%. J)These developments also bring some health benefits, according to a report from the MacArthur Foundation s research group on successful ageing. The group found that thos
13、e elderly people who were able to retain a sense of independence were more likely to stay healthy in old age. K)Maintaining a level of daily physical activity may help mental functioning, says Carl Cotman, a neuroscientist at the University of California at Irvine. He found that rats that exercise o
14、n a treadmill have raised levels of brain-derived neurotrophic factor coursing through their brains. Cotman believes this hormone, which keeps neurons functioning, may prevent the brains of active humans from deteriorating. L)As part of the same study, Teresa Seeman, a social epidemiologist at the U
15、niversity of Southern California in Los Angeles, found a connection between self-esteem and stress in people over 70. In laboratory simulations of challenging activities such as driving, those who felt in control of their lives pumped out lower levels of stress hormones such as cortical. Chronically
16、 high levels of these hormones have been linked to heart disease. M)But independence can have drawbacks. Seeman found that elderly people who felt emotionally isolated maintained higher levels of stress hormones even when asleep. The research suggests that older people fare best when they feel indep
17、endent but know they can get help when they need it. N)“Like much research into ageing, these results support common sense“, says Seeman. They also show that we may be underestimating the impact of these simple factors. “The sort of thing that your grandmother always told you turns out to be right o
18、n target“, she says. 1 There has been a considerable reduction in the number of elderly people who are disabled. 2 A demographer claims that many diseases are affecting people later in life than they did in the past. 3 A study lasting fourteen years shows that fewer elderly people are suffering from
19、 diseases. 4 The reasons why educated people are more likely to live longer are that they earn more money and focus on medical care. 5 Those elderly people who maintain a sense of self-reliance are able to keep healthy. 6 Diseases related with old age such as arthritis, high blood pressure and circu
20、lation problems are facing a declining trend. 7 Increases in some other illnesses may be due to changes in personal habits and to environment pollution. 8 Regular amounts of exercise may help prevent mental decline. 9 Development in medicine is attributable to the decline of certain diseases. 10 Fee
21、lings of control over life can reduce stress in difficult situations. 10 A Very Special Dog A)It is 8:15 a.m. A flight lands at Melbournes Tullamarine International Airport. Several hundred pieces of baggage are rushed from the plane onto a conveyor belt in the baggage reclaim annexe. Over the sound
22、 of roaring engines, rushing air vents and grinding generators, a dog barks. Florence, a sleek black labrador, wags her tail. B)Among the cavalcade of luggage passing beneath Florence s all-smelling nose, is a nondescript hardback suitcase. Inside the case, within styrofoam casing, packed in loose p
23、epper and coffee, wrapped in freezer paper and heat-sealed in plastic, are 18 kilograms of hashish. C)The cleverly concealed drugs dont fool super-sniffer Florence, and her persistent scratching at the case alerts her handler. Florence is one of a truly new breed: the product of what is perhaps the
24、only project in the world dedicated to breeding dogs solely to detect drugs. Ordinary dogs have a 0.1% chance of making it in drug detection. The new breeding programme, run by the Australian Customs, is so successful that more than 50% of its dogs make the grade. D)And what began as a wholly practi
25、cal exercise in keeping illegal drugs out of Australia may end up playing a role in an entirely different sphere the comparatively esoteric world of neurobiology. It turns out that it s not Florence s nose that makes her a top drug dog, but her unswerving concentration, plus a few other essential tr
26、aits. E)Florence could help neurobiologists to understand both what they call “attention processing“, the brain mechanisms that determine what a person pays attention to and for how long, and its flip side, problems such as Attention Deficit / Hyperactivity Disorder(ADHD). As many as 3 to 5% of chil
27、dren are thought to suffer from the condition in the US, where the incidence is highest, although diagnosis is often controversial. F)The Australian Customs has used dogs to find drugs since 1969. Traditionally, the animals came from pounds and private breeders. But, in 1993, fed up with the poor su
28、ccess rate of finding good dogs this way, John Vandeloo, senior instructor with the Detector Dog Unit, joined forces with Kath Champness, then a doctoral student at the University of Melbourne, and set up a breeding programme. G)Champness began by defining six essential traits that make a detector d
29、og. First, every good detector dog must love praise because this is the only tool trainers have at their disposal, but the dog must still be able to work for long periods without it. H)Then it needs a strong hunting instinct and the stamina to keep sniffing at the taxing rate of around 300 times per
30、 minute. The ideal detector is also fearless enough to deal with jam-packed airport crowds and the roaring engine rooms of cargo ships. I)The remaining two traits are closely related and cognitive in nature. A good detector must be capable of focusing on the task of searching for drugs, despite the
31、distractions in any airport or dockside. This is what neurobiologists call “selective attention“. And finally, with potentially tens of thousands of hiding places for drugs, the dog must persevere and maintain focus for hours at a time. Neurobiologists call this “sustained attention“. J)Vandeloo and
32、 Champness assess the dogs abilities to concentrate by marking them on a scale of between one and five according to how well they remain focused on a toy tossed into a patch of grass. K)Ivan scores a feeble one. He follows the toy, gets half-way there, then becomes distracted by places where the oth
33、er dogs have been or by flowers in the paddock. Rowena, on the other hand, has phenomenal concentration; some might even consider her obsessive. When Vandeloo tosses the toy, nothing can distract her from the searching, not other dogs, not food. And even if no one is around to encourage her, she kee
34、ps looking just the same. Rowena gets a five. L)A persons ability to pay attention, like a dogs, depends on a number of overlapping cognitive behaviours, including memory and learning the neurobiologist s attention processing. M)Attention in humans can be tested by asking subjects to spot colours on
35、 a screen while ignoring shapes, or to spot sounds while ignoring visual cues, or to take a vigilance test. Sitting a vigilance test is like being a military radar operator. Blips appear on a cluttered monitor infrequently and at irregular intervals. Rapid detection of all blips earns a high score.
36、Five minutes into the test, one in ten subjects will start to miss the majority of the blips, one in ten will still be able to spot nearly all of them and the rest will come somewhere in between. N)Vigilance tasks provide signals that are infrequent and unpredictable which is exactly what is expecte
37、d of the dogs when they are asked to notice just a few odour molecules in the air, and then to home in on the source. During a routine mail screen that can take hours, the dogs stay so focused that not even a postcard lined with 0.5 grams of heroin and hidden in a bulging sack of letters escapes det
38、ection. O)With the current interest in attentional processing, as well as human conditions that have an attention deficit component, such as ADHD, it is predicted that it is only a matter of time before the super-sniffer dogs attract the attention of neurobiologists trying to cure these conditions.
39、11 On a conveyor belt at luggage claim area are lots of pieces of luggage carried from the plane. 12 There are diversified methods to examine peoples attention like spotting colours instead of images or distinguishing auditory clues rather than seeing. 13 The previous way of finding qualified dogs h
40、as been proved to be lack of efficiency. 14 The reason why Rowena received five scores is that she still continues to work without encouragement. 15 Florence, a typically new breed of dog, is simply served to detect drugs. 16 Florence is a good drug detector because she is not easily distracted othe
41、r than having a sensitive nose. 17 Selective attention and sustained attention are the two other essential features which are connected with each other. 18 Similar to that of dogs, peoples competence to concentrate is based on some cognitive activities like memory and learning. 19 Dogs like Florence
42、 may help scientists comprehend the mechanisms of human beings brain. 20 Those recurring signals are to test whether drug detectors can notice them or not. 20 Why Pagodas Dont Fall Down A)In a land swept by typhoons and shaken by earthquakes, how have Japans tallest and seemingly flimsiest old build
43、ings 500 or so wooden pagodas remained standing for centuries? Records show that only two have collapsed during the past 1400 years. Those that have disappeared were destroyed by fire as a result of lightning or civil war. B)The disastrous Hanshin earthquake in 1995 killed 6,400 people, toppled elev
44、ated highways, flattened office blocks and devastated the port area of Kobe. Yet it left the magnificent five-storey pagoda at the Toji temple in nearby Kyoto unscathed, though it levelled a number of buildings in the neighbourhood. C)Japanese scholars have been mystified for ages about why these ta
45、ll, slender buildings are so stable. It was only thirty years ago that the building industry felt confident enough to erect office blocks of steel and reinforced concrete that had more than a dozen floors. With its special shock absorbers to dampen the effect of sudden sideways movements from an ear
46、thquake, the thirty-six-storey Kasumigaseki building in central TokyoJapans first skyscraper was considered a masterpiece of modern engineering when it was built in 1968. D)Yet in 826, with only pegs and wedges to keep his wooden structure upright, the master builder Kobodaishi had no hesitation in
47、sending his majestic Toji pagoda soaring fifty-five metres into the sky nearly half as high as the Kasumigaseki skyscraper built some eleven centuries later. Clearly, Japanese carpenters of the day knew a few tricks about allowing a building to sway and settle itself rather than fight nature s force
48、s. But what sort of tricks? E)The multi-storey pagoda came to Japan from China in the sixth century. As in China, they were first introduced with Buddhism and were attached to important temples. The Chinese built their pagodas in brick or stone, with inner staircases, and used them in later centurie
49、s mainly as watchtowers. F)When the pagoda reached Japan, however, its architecture was freely adapted to local conditions they were built less high, typically five rather than nine storeys, made mainly of wood and the staircase was dispensed with because the Japanese pagoda did not have any practical use but became more of an art object. Because of the typhoons that batter Japan in the summer, Japanese builders learned to extend the eaves of buildings further beyond the walls. This prevents rainwater gushing down the wa
