大学英语六级分类模拟题460及答案解析.doc
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1、大学英语六级分类模拟题 460 及答案解析(总分:366.00,做题时间:90 分钟)一、Part Writing(总题数:1,分数:106.50)1.Directions : For this part, you are allowed 30 minutes to write a short essay on invention. Your essay should include the importance of invention and measures to be taken to encourage invention. You are required to wrote at
2、least 150 words but no more than 200 words. (分数:106.50)_二、Part Reading Compr(总题数:0,分数:0.00)三、Section A(总题数:1,分数:71.00)Animals on the MoveA. It looked like a scene from “Jaws“ but without the dramatic music. A huge shark was slowly swimming through the water, its tail swinging back and forth like the
3、 pendulum of a clock. Suddenly sensitive nerve ending in the shark“s skin picked up vibrations of a struggling fish. The shark was immediately transformed into a deadly, efficient machine of death. With muscles taut, the shark knifed through the water at a rapid speed. In a flash the shark caught it
4、s victim, a large fish, in its powerful jaws. Then, jerking its head back and forth, the shark tore huge chunks of flesh from its victim and swallowed them. Soon the action was over. B. Moving to Survive In pursuing its prey, the shark demonstrated in a dramatic way the important role of movement, o
5、r locomotion, in animals. Like the shark, most animals use movement to find food. They also use locomotion to escape enemies, find a mate, and explore new territories. The methods of locomotion include crawling, hopping, slithering, flying, swimming, or walking. Humans have the added advantage of us
6、ing their various inventions to move about in just about any kind of environment. Automobiles, rockets, and submarines transport humans from deep oceans to as far away as the moon. However, for other animals movement came about naturally through millions of years of evolution. One of the most succes
7、sful examples of animal locomotion is that of the shark. Its ability to quickly zero in on its prey has always impressed scientists. But it took a detailed study by Duke University marine biologists S. A. Wainwright, F. Vosburgh, and J. H. Hebrank to find out how the sharks did it. In their study th
8、e scientists observed sharks swimming in a tank at Marine land in Saint Augustine, Fla. Movies were taken of the sharks“ movements and analyzed. Studies were also made of shark skin and muscle. C. Skin Is the Key The biologists discovered that the skin of the shark is the key to the animal“s high ef
9、ficiency in swimming through the water. The skin contains many fibers that crisscross like the inside of a belted radial tire. The fibers are called collagen fibers. These fibers can either store or release large amounts of energy depending on whether the fibers are relaxed or taut. When the fibers
10、are stretched, energy is stored in them the way energy is stored in the string of a bow when pulled tight. When the energy is released, the fibers become relaxed. D. The Duke University biologists have found that the greatest stretching occurs where the shark bends its body while swimming. During th
11、e body“s back and forth motion, fibers along the outside part of the bending body stretch greatly. Much potential energy is stored in the fibers. This energy is released when the shark“s body snaps back the other way. As energy is alternately stored and released on both sides of the animal“s body, t
12、he tail whips strongly back and forth. This whip-like action propels the animal through the water like a living bullet. E. Source of Energy What causes the fibers to store so much energy? In finding the answer the Duke University scientists learned that the shark“s similarity to a belted radial tire
13、 doesn“t stop with the skin. Just as a radial tire is inflated by pressure, so, too, is the area just under the shark“s collagen “radials“. Instead of air pressure, however, the pressure in the shark may he due to the force of the blood pressing on the collagen fibers. F. When the shark swims slowly
14、, the pressure on the fibers is relatively low, and the shark is able to bend its body at sharp angles. The animal swims this way when looking around for food or just swimming. However, when the shark detects an important food source, some fantastic involuntary changes take place. The pressure insid
15、e the animal may increase by 10 times. This pressure change greatly stretches the fibers, enabling much energy to be stored. This energy is then transferred to the tail, and the shark is off. The rest of the story is predictable. G. Dolphin Has Speed Record Another fast marine animal is the dolphin.
16、 This seagoing mammal has been clocked at speeds of 32 kilometers (20 miles) an hour. Biologists studying the dolphin have discovered that, like the shark, the animal“s efficient locomotion can be traced to its skin. A dolphin“s skin is made up in such a way that it offers very little resistance to
17、the water flowing over it. Normally when a fish or other object moves slowly through the water, the water flows smoothly past the body. This smooth flow is known as laminar flow. However, at faster speeds the water becomes more turbulent along the moving fish. This turbulence muses friction and slow
18、s the fish down. H. In a dolphin the skin is so flexible that it bends and yields to the waviness of the water. The waves, in effect, become tucked into the skin“s folds. This allows the rest of the water to move smoothly by in a laminar flow. Where other animals would be slowed by turbulent water a
19、t rapid speeds, the dolphin can race through the water at record breaking speeds. I. Other Animals Less Efficient Not all animals move as efficiently as sharks and dolphins. Perhaps the greatest loser in locomotion efficiency is the slug. The slug, which looks like a snail without a shell, lays down
20、 a slimy trail over which it crawls. It uses so much energy producing the slimy mucus and crawling over it that a mouse traveling the same distance uses only one twelfth as much energy. J. Scientists say that because of the slug“s inefficient use of energy, its lifestyle must be restricted. That is,
21、 the animals are forced to confine themselves to small areas for obtaining food and finding proper living conditions. Have humans ever been faced with this kind of problem?(分数:71.00)(1).A dolphin“s skin enables it to pass through with little resistance to the water flowing over it.(分数:7.10)(2).A sha
22、rk finds its prey by feeling the vibrations of a struggling prey.(分数:7.10)(3).According to the scientists, when bending its body in swimming, the shark stretches its collagen fibers to the greatest extent.(分数:7.10)(4).Animals are restricted to small areas tot obtaining food and finding proper living
23、 conditions.(分数:7.10)(5).Automobiles, rockets, and submarines exemplify that human inventions enable us to travel in almost any kind of environment.(分数:7.10)(6).Consuming the equal amount of energy as a slug does, a mouse can travel 12 times as long as a slug.(分数:7.10)(7).Dolphin wouldn“t be bothere
24、d by turbulent water at rapid speeds like other animals.(分数:7.10)(8).One of the main reasons sharks are such effective predators is their skin.(分数:7.10)(9).Sharks are a notable example of fish that depend on locomotion to survive.(分数:7.10)(10).The area just under the shark“s collagen fibers is simil
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