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1、大学四级考试 20102010 年 12 月大学英语四级考试全真预测试题2010 年 12 月 14 日 11:39 文都教育我要评论(0)字号：T|TPart Writing(30 minutes)Directions: For this part, you are allowed 30 minutes to write a composition on the topic Generation Gap. You should write at least 120 words following the outline given below in Chinese:1. 代沟的表现。2. 代
2、沟出现的家庭原因。3. 代沟出现的社会原因。Generation GapPart 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 on Answer Sheet 1. For questions 1-7, choose the best answer from the four choices marked A), B
3、), C) and D). For question 8-10, complete the sentences with the information given in the passage.Animals on the MoveIt looked 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.Sud
4、denly sensitive nerve ending in the shark 餾 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 its victim, a large fish, i
5、n 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.Moving to SurviveIn pursuing its prey, the shark demonstrated in a dramatic way the important role of movement, or locomotion, in animals.Like
6、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 using their various inventions to
7、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 successful examples of animal locomoti
8、on 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 the scientists observed sharks swi
9、mming 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.Skin Is the Key吗 The biologists discovered that the skin of the shark is the key to the animals high efficiency in swimming through the wate
10、r. 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 are stretched, energy is stored in th
11、em the way energy is stored in the string of a bow when pulled tight. When the energy is released, the fibers become relaxed.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 alo
12、ng the outside part of the bending body stretch greatly. Much potential energy is stored in the fibers. This energy is released 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 w
13、hip-like action propels the animal through the water like a living bullet.Source of EnergyWhat causes the fibers to store so much energy? In finding the answer the Duke University scientists learned that the shark 餾 similarity to a belted radial tire doesn 餿 stop with the skin. Just as a radial tire
14、 is inflated by pressure, so, too, is the area just under the shark 餾 collagen “radials”. Instead of air pressure, however, 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 fi
15、bers are more relaxed, 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 inside the animal may increase
16、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.Dolphin Has Speed RecordAnother 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 shark, the animals efficient locomotion can be traced to its skin. A dolphi
