[外语类试卷]大学英语四级模拟试卷916及答案与解析.doc
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1、大学英语四级模拟试卷 916及答案与解析 一、 Part I Writing (30 minutes) 1 Killing Time Indoors 1现在有不少人业余时间喜欢 “宅 ”在家里 2人们对这种做法有不同看法 3我的看法 二、 Part II Reading Comprehension (Skimming and Scanning) (15 minutes) Directions: In this part, you will have 15 minutes to go over the passage quickly and answer the questions attach
2、ed to the passage. For questions 1-7, mark: Y (for YES) if the statement agrees with the information given in the passage; N (for NO) if the statement contradicts the information given in the passage; NG (for NOT GIVEN) if the information is not given in the passage. 1 Animals on the Move It looked
3、like a scene from “Jaws“ but without the dramatic music. A huge shark was lowly swimming through the water, its tail swinging back and forth like the pendulum of a clock. Suddenly sensitive nerve ending in the sharks skin picked up vibrations of a struggling fish. The shark was immediately transform
4、ed 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 its 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 t
5、hem. Soon the action was over. Moving to Survive In pursuing its prey, the shark demonstrated in a dramatic way the important role of movement, or 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
6、territories. The methods of locomotion include crawling, hopping, slithering, flying, swimming, or walking. Humans have the added advantage of using their various inventions to move about in just about any kind of environment. Automobiles, rockets, and submarines transport humans from deep oceans to
7、 as far away as the moon. However, for other animals movement came about naturally through millions of years of evolution. One of the most successful 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
8、 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 the scientists observed sharks swimming in a tank at Marine land in Saint Augustine, Fla. Movies were taken of the sharks movements and analyzed. Studies wer
9、e also made of shark skin and muscle. Skin Is the Key The biologists discovered that the skin of the shark is the key to the animals high efficiency 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 fi
10、bers. These fibers can either store or release large amounts of energy depending on whether the fibers are relaxed or taut. When the fibers 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 relaxe
11、d. The Duke University biologists have found that the greatest stretching occurs where the shark bends its body while swimming. During the bodys 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 rel
12、eased when the sharks body snaps back the other way. As energy is alternately stored and released on both sides of the animals body, the tail whips strongly back and forth. This whip-like action propels the animal through the water like a living bullet. Source of Energy What causes the fibers to sto
13、re so much energy? In finding the answer the Duke University scientists learned that the sharks similarity to a belted radial tire doesnt stop with the skin. Just as a radial tire is inflated by pressure, so, too, is the area just under the sharks collagen “radials“. Instead of air pressure, however
14、, the pressure in the shark may be due to the force of the blood pressing on the collagen fibers. When the shark swims slowly, the pressure on the fibers is relatively low. The fibers are more relaxed, and the shark is able to bend its body at sharp angles. The animal swims this way when looking aro
15、und for food or just swimming. However, when the shark detects an important food source, some fantastic involuntary changes take place. The pressure inside the animal may increase by 10 times. This pressure change greatly stretches the fibers, enabling much energy to be stored. This energy is then t
16、ransferred to the tail, and the shark is off. The rest of the story is predictable. Dolphin Has Speed Record Another fast marine animal is the dolphin. This seagoing mammal has been clocked at speeds of 32 kilometers (20 miles) an hour. Biologists studying the dolphin have discovered that, like the
17、shark, the animals efficient locomotion can be traced to its skin. A dolphins skin is made up in such a way that it offers very little resistance to 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 flo
18、w is known as laminar flow. However, at faster speeds the water becomes more turbulent along the moving fish. This turbulence muses friction and slows the fish down. 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 t
19、he skins 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 at rapid speeds, the dolphin can race through the water at record breaking speeds. Other Animals Less Efficient Not all animals move as efficiently as shark
20、s and dolphins. Perhaps the greatest loser in locomotion efficiency is the slug. The slug, which looks like a snail without a shell, lays down 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
21、one twelfth as much energy. Scientists say that because of the slugs inefficient use of energy, its lifestyle must be restricted. That is, 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 o
22、f problem? 2 According to the passage, a shark can use movement to do something except_. ( A) to find food ( B) to avoid being chased by its enemies ( C) to find a new place to live ( D) to show its braveness 3 Examples of automobiles, rockets and submarines are used to show that_. ( A) humans are t
23、he most clever living creatures in the world ( B) human inventions enable us to travel in almost any kind of environment ( C) humans are very successful in inventing transportation tools ( D) humans cant move like other animals in any circumstances 4 What is the key to the sharks swift locomotion in
24、 water? ( A) The skin. ( B) The tail. ( C) The muscle. ( D) The jaw. 5 According to the Duke University scientists, when does the shark stretch its collagen fibers to the greatest extent? ( A) When moving its tail rapidly. ( B) When finding its preys. ( C) When staying without any movement. ( D) Whe
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- 外语类 试卷 大学 英语四 模拟 916 答案 解析 DOC
