1、大学英语六级改革适用（阅读）模拟试卷 18及答案与解析 Section B 0 Play Is a Serious Business A)Playing is a serious business. Children engrossed in a make-believe world, fox cubs play-fighting or kittens teaming a ball of string arent just having fun. Play may look like a carefree and exuberant way to pass the time before th
2、e hard work of adulthood comes along, but there s much more to it than that. B)For a start, play can even cost animals their lives. Eighty percent of deaths among juvenile fur seals occur because playing pups fail to sport predators approaching. It is also extremely expensive in terms of energy. Pla
3、yful young animals use around two or three per cent of energy cavorting, and in children that figure can be closer to fifteen per cent. “Even two or three per cent is huge,“ says John Byers of Idaho University. “You just dont find animals wasting energy like that,“ he adds. There must be a reason. C
4、)But if play is not simply a developmental hiccup, as biologists once thought, why did it evolve? The latest idea suggests that play has evolved to build big brains. In other words, playing makes you intelligent. Playfulness, it seems, is common only among mammals, although a few of the larger-brain
5、ed birds also indulge. Animals at play often use unique signs tail-wagging in dogs, for example to indicate that activity superficially resembling adult behaviour is not really in earnest. D)A popular explanation of play has been that it helps juveniles develop the skills they will need to hunt, mat
6、e and socialise as adults. Another has been that it allows young animals to get in shape for adult life by improving their respiratory endurance. Both these ideas have been questioned in recent years. E)Take the exercise theory. If play evolved to build muscle or as a kind of endurance training, the
7、n you would expect to see permanent benefits. But Byers points out that the benefits of increased exercise disappear rapidly after training stops, so many improvement in endurance resulting from juvenile play would be lost by adulthood. F)“If the function of play was to get into shape,“ says Byers,
8、“the optimum time for playing would depend on when it was most advantageous for the young of a particular species to do so. But it doesnt work like that.“ Across species, play tends to peak about halfway through the suckling stage and then decline. G)Then there s the skills-training hypothesis. At f
9、irst glance, playing animals do appear to be practising the complex manoeuvres they will need in adulthood. But a closer inspection reveals this interpretation as too simplistic. In one study, behavioural ecologist Tim Caro, from the University of California, looked at the predatory play of kittens
10、and their predatory behaviour when they reached adulthood. He found that the way the cats played had no significant effect on their hunting prowess in later life. H)Earlier this year, Sergio Pellis of Lethbridge University, Canada, reported that there is a strong positive link between brain size and
11、 playfulness among mammals in general. Comparing measurements for fifteen orders of mammals, he and his team found large brains(for a given body size)are linked to greater playfulness. The converse was also found to be true. I)Robert Barton of Durham University believes that, because large brains ar
12、e more sensitive to developmental stimuli than smaller brains, they require more play to help mould them for adulthood. “I concluded it s to do with learning and with the importance of environmental data to the brain during development,“ he says. J)According to Byers, the timing of the playful stage
13、 in young animals provides an important clue to what s going on. If you plot the amount of time juvenile devotes to play each day over the course of its development, you discover a pattern typically associated with a “sensitive period“ a brief development window during which the brain can actually b
14、e modified in ways that are not possible earlier or later in life. K)Think of the relative ease with which young children but not infants or adultsabsorb language. Other researchers have found that play in cats, rats and mice is at its most intense just as this “window of opportunity“ reaches its pe
15、ak. L)“People have not paid enough attention to the amount of the brain activated by plays,“ says Marc Bekoff from Colorado University. Bekoff studied coyote pups at play and found that the kind of behaviour involved was markedly more variable and unpredictable than that of adults. Such behaviour ac
16、tivates many different parts of the brain, he reasons. Bekoff likens it to a behavioural kaleidoscope, with animals at play jumping rapidly between activities. “They use behaviour from a lot of different contexts predation, aggression, reproduction,“ he says. “Their developing brain is getting all s
17、orts of stimulation.“ M)Not only is more of the brain involved in play that was suspected, but it also seems to activate higher cognitive processes. “There s enormous cognitive involvement in play,“ says Bekoff. He points out that play often involves complex assessments of playmates, ideas of recipr
18、ocity and the use of specialised signals and rules. He believes that play creates a brain that has greater behavioural flexibility and improved potential for learning later in life. N)The idea is backed up by the work of Stephen Siviy of Gettysburg College. Siviy studied how bouts of play affected t
19、he brain s levels of particular chemical associated with the stimulation and growth of nerve cells. He was surprised by the extent of the activation. “Play just lights everything up,“ he says. By allowing link-ups between brain areas that might not normally communicate with each other, play may enha
20、nce creativity. O)What might further experimentation suggest about the way children are raised in many societies today? We already know that rat pups denied the chance to play grow smaller brain components and fail to develop the ability to apply social rules when they interact with their peers. Wit
21、h schooling beginning earlier and becoming increasingly exam-orientated, play is likely to get even less of a look-in. Who knows what the result of that will be? 1 A wide range of activities are combined during play. 2 Play is related to learning, and provides input concerning physical surroundings.
22、 3 There is a link between a specific substance in the brain and playing. 4 Byers thinks that play is not a form of fitness training for the future. 5 If you record how much time young animals spend playing each day over the course of its development, youll discover a sensitive period. 6 A reduction
23、 in play opportunities might possibly affect children. 7 Play is functional because the brain needs it for development. 8 Play consumes about fifteen percent of children s energy. 9 Some cognitive activities are exercised and developed during play. 10 There is a tendency for mammals with smaller bra
24、ins to play less. 10 Volcanoes Earth-shattering News A)Volcanoes are the ultimate earth-moving machinery. A violent eruption can blow the top few kilometres off a mountain, scatter fine ash practically all over the globe and hurt rock fragments into the stratosphere to darken the skies a continent a
25、way. B)But the classic eruption cone-shaped mountain, big bang, mushroom cloud and surges of molten lava is only a tiny part of a global story. Volcanism, the name given to volcanic processes, really has shaped the world. Eruptions have rifted continents, raised mountain chains, constructed islands
26、and shaped the topography of the earth. The entire ocean floor has a basement of volcanic basalt. C)Volcanoes have not only made the continents, they are also thought to have made the world s first stable atmosphere and provided all the water for the oceans, rivers and ice-caps. D)There are now abou
27、t 600 active volcanoes. Every year they add two or three cubic kilometres of rock to the continents. Imagine a similar number of volcanoes smoking away for the last 3,500 million years. That is enough rock to explain the continental crust. E)What comes out of volcanic craters is mostly gas. More tha
28、n 90% of this gas is water vapour from the deep earth: enough to explain, over 3,500 million years, the water in the oceans. The rest of the gas is nitrogen, carbon dioxide, sulphur dioxide, methane, ammonia and hydrogen. The quantity of these gases, again multiplied over 3,500 million years, is eno
29、ugh to explain the mass of the world s atmosphere. We are alive because volcanoes provided the soil, air and water we need. F)Geologists consider the earth as having a molten core, surrounded by a semi-molten mantle and a brittle, outer skin. It helps to think of a soft-boiled egg with a runny yolk,
30、 a firm but squishy white and a hard shell. If the shell is even slightly cracked during boiling, the white material bubbles out and sets like a tiny mountain chain over the crack like an archipelago of volcanic islands such as the Hawaiian Islands. But the earth is so much bigger and the mantle bel
31、ow is so much halter. G)Even though the mantle rocks are kept solid by overlying pressure, they can still slowly “flow“ like thick treacle. The flow, thought to be in the form of convection currents, is powerful enough to fracture the “eggshell“ of the crust into plates, and keep them bumping and gr
32、inding against each other, or even overlapping, at the rate of a few centimetres a year. These fracture zones, where the collisions occur, are where earthquakes happen. And, very often, volcanoes. H)These zones are lines of weakness, or hot spots. Every eruption is different, but put at its simplest
33、, where there are weaknesses, rocks deep in the mantle, heated to 1,350C, will start to expand and rise. As they do so, the pressure drops, and they expand and become liquid and rise more swiftly. I)Sometimes it is slow: vast bubbles of magma molten rock from the mantle inch towards the surface, coo
34、ling slowly, to show through as granite extrusions(as on Skye, or the Great Whin Sill, the lava dyke squeezed out like toothpaste that carries part of Hadrian s Wall in northern England). J)Sometimes as in Northern Ireland, Wales and the Karoo in South Africa the magma rose faster, and then flowed o
35、ut horizontally on to the surface in vast thick sheets. In the Deccan plateau in western India, there are more than two million cubic kilometres of lava, some of it 2,400 metres thick, formed over 500,000 years of slurping eruption. K)Sometimes the magma moves very swiftly indeed. It does not have t
36、ime to cool as it surges upwards. The gases trapped inside the boiling rock expand suddenly, the lava glows with heat, it begins to froth, and it explodes with tremendous force. Then the slightly cooler lava following it begins to flow over the lip of the crater. It happens on Mars, it happened on t
37、he moon, it even happens on some of the moons of Jupiter and Uranus. L)By studying the evidence, vulcanologists can read the force of the great blasts of the past. Is the pumice light and full of holes? The explosion was tremendous. Are the rocks heavy, with huge crystalline basalt shapes, like the
38、Giant s Causeway in Northern Ireland? It was a slow, gentle eruption. M)The biggest eruption are deep on the mid-ocean floor, where new lava is forcing the continents apart and widening the Atlantic by perhaps five centimetres a year. Look at maps of volcanoes, earthquakes and island chains like the
39、 Philippines and Japan, and you can see the rough outlines of what are called tectonic plates the plates which make up the earths crust and mantle. The most dramatic of these is the Pacific “ring of fire“ where there have the most violent explosions Mount Pinatubo near Manila, Mount St Helen s in th
40、e Rockies and El Chicho n in Mexico about a decade ago, not to mention world-shaking blasts like Krakatoa in the Sunda Straits in 1883. N)But volcanoes are not very predictable. That is because geological time is not like human time. During quiet periods, volcanoes cap themselves with their own lava
41、 by forming a powerful cone from the molten rocks slopping over the rim of the crater; later the lava cools slowly into a huge, hard, stable plug which blocks any further eruption until the pressure below becomes irresistible. In the case of Mount Pinatubo, this took 600 years. O)Then, sometimes, wi
42、th only a small warning, the mountain blows its top. It did this at Mont Pelee in Martinique at 7.49 a.m. on 8 May, 1902. Of a town of 28,000, only two people survived. In 1815, a sudden blast removed the top 1,280 metres of Mount Tambora in Indonesia. The eruption was so fierce that dust thrown int
43、o the stratosphere darkened the skies, canceling the following summer in Europe and North America. Thousands starved as the harvest failed, after snow in June and frosts in August. Volcanoes are potentially world news, especially the quiet ones. 11 Mount Pinatubo remained inactive for 600 years. 12
44、Apart from shaping the earths land surface, volcanic eruptions have also produced the world s atmosphere and water. 13 The earthquake zone on the Pacific Ocean is known as “ring of fire“, where the most violent explosions happened. 14 Sometimes volcanoes erupt without a clear warning sign but end up
45、 with heavy casualties. 15 The flow of the mantle rocks is so powerful that it splits the outer crust into plates. 16 A third type of eruption occurs when the lava emerges very quickly and explodes violently. 17 The fracture zones are places of weakness, where earthquakes happen frequently. 18 Activ
46、e volcanoes add two or three cubic kilometres of rock to the earth per year. 19 Sometimes the magma moves slowly and forms outcrops of granite on the earth s surface. 20 Volcanic eruptions have split continents, lifted mountain chains, formed islands, and finally determined the topographic shape of
47、the earth. 20 The Nature and Aims of Archaeology Introduction A)Archaeology is partly the discovery of the treasures of the past, partly the meticulous work of the scientific analyst, partly the exercise of the creative imagination. It is toiling in the sun on an excavation in the deserts of Central
48、 Asia; it is working with living Inuit in the snows of Alaska. It is diving down to Spanish wrecks off the coast of Florida, and it is investigating the sewers of Roman York. But it is also the painstaking task of interpretation so that we come to understand what these things mean for the human stor
49、y. And it is the conservation of the world s cultural heritage against looting and against careless destruction. B)Archaeology, then, is both a physical activity out in the field, and an intellectual pursuit in the study or laboratory. That is part of its great attraction. The rich mixture of danger and detective work has also made it the perfect vehicle for fiction writers and film-makers, from Agatha Christie with Murder in Mesopotamia to Steven Spielberg with Indiana Jones. However far from reality such portrayals may be, t
