[外语类试卷]大学英语四级模拟试卷238及答案与解析.doc
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1、大学英语四级模拟试卷 238及答案与解析 一、 Part I Writing (30 minutes) 1 For this part, you are allowed 30 minutes to write an essay with no less than 120 words based on the following directions. First you are required to decide on a proper topic and then supply the necessary information to complete each paragraph. Re
2、member to write neatly. 1. 请指出下面这段话的寓意。 2. 分析造成的原因。 3. 提出解决该问题的措施或设想。 祖上以打猎为生 爷爷以卖上等木材为生 父亲以卖劈柴和柴墩为生 儿子以卖根雕原料为生 孙子以卖黄沙为生 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 at
3、tached 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 Japanese Computer Is World
4、s Fastest, as U.S. Falls Back The worlds fastest computer A Japanese laboratory has built the worlds fastest computer, a machine so powerful that it matches the raw processing power of the 20 fastest American computers combined and far outstrips the previous leader, an 1. B. M. -built machine. The a
5、chievement, which was reported today by an American scientist who tracks the performance of the worlds most powerful computers, is evidence that a technology race that most American engineers thought they were winning handily is far from over. American companies have built the fastest computers for
6、most of the last decade. The accomplishment is also a vivid statement of contrasting scientific and technology priorities in the United States and Japan. The Japanese machine was built to analyze climate change, including global warming, as well as weather and earthquake patterns. By contrast, the U
7、nited States has predominantly focused its efforts on building powerful computers for simulating weapons, while its efforts have lagged in scientific areas like climate modeling. A competition between Japan and U. S. For some American computer scientists, the arrival of the Japanese supercomputer ev
8、okes the type of alarm raised by the Soviet Unions Sputnik(人造地求卫星 )satellite in 1957. Several United States computer scientists said the Japanese machine reflected differences in style and commitment that suggest that United States research and spending efforts have grown complacent (自满的 )in recent
9、years. For now, the new computer will be used only for climate research, and American scientists have already begun preparing to move some of their climate simulation research to run on the Japanese machine. “The Japanese clearly have a level of will that we havent achieved,“ said Thomas Sterling, a
10、 computer designer at the California Institute of Technology. “These guys are blowing us out of the water, and we need to sit up and take notice.“ Wide applications of the magic power The new Japanese supercomputer will have both scientific and practical applications. It will be used for advanced mo
11、deling of theories about global warming and climate change, and it will be able to predict short-term weather patterns. Advances in computer speed today routinely extend computer simulation into all areas of science and engineering as complex calculations take an increasingly shorter time. Because i
12、ncreases in computing power tend to have exponential (指数的 )results, a problem that could take years for even the fastest computers today might be finished in hours on the new Japanese computer. The ability to track the path of a typhoon, for example, is of immediate relevance to the island nation of
13、 Japan. Improved prediction made possible by a more powerful computer might save lives and property. Computer simulation has become a standard tool in both science and modern design of products ranging from drugs to bicycles. Computers that are more powerful make possible simulations that are more a
14、ccurate and can reduce cost and increase efficiency. At one time, for example, computers were capable of computing the flow of air over a single airplane wing but can now cover the entire aircraft. The new Japanese supercomputer was financed by the Japanese government and has been installed at the E
15、arth Simulator Research and Development Center in Yokohama (横滨 ), west of Tokyo. The Japanese government spent $ 350 million to $ 400 million developing the system over the last five years, according to Dr. Akira Sekino, president and chief executive of HNSX Supercomputers, a unit of the NEC Corpora
16、tion based in Littleton, Colo. The new computer was formally dedicated last month, and the Japan Marine Science and Technology Center said yesterday that the machine had reached more than 87 percent of its theoretical peak speed. NEC sells a scaled-down version of the new supercomputer. Several Unit
17、ed States universities and government agencies have tried to buy the machines over the lust decade for purposes like aircraft simulation, seismic (地震的 )studies and molecular modeling. But sales have been thwarted (反对 )by resistance from the Commerce Department and members of Congress, who complained
18、 that NEC was “dumping“ the machines, or selling them below cost. Last year Cray Inc., a United States maker of supercomputers, entered into a marketing agreement to sell the machines in the United States, but no sales have been announced. A new machine The NEC supercomputers are based on vector pro
19、cessing (矢量处理 ), a way of using specialized hardware to solve complex calculations that was pioneered by the American supercomputer designer Seymour Cray. The concept has generally fallen out of favor in the United States in recent years. Assembled from 640 specialized modes that are in turn compose
20、d of 5104 processors made by NEC, the new Japanese supercomputer occupies the space of four tennis courts and has achieved a computing speed of 35.6 trillion mathematical operations a second. The processors are linked in a way that allows extremely efficient operation compared with the previously fa
21、stest “massively parallel“ computers, which are based on standard parts rather than custom-made chips. The earth simulator project is intended to create a “virtual earth“ on an NEC supercomputer to show what the world will look like under various climate conditions by means of advanced numerical sim
22、ulation. The system is intended to serve as a research platform for international teams of researchers, and United States scientists are planning to participate in new projects made possible by the more powerful computer. By comparison, the fastest American supercomputer, which until now held the wo
23、rld computing speed record, is the ASCI White Pacific computer at the Lawrence Livermore National Laboratory in California. Based on I. B. M. processors, it has achieved a top speed of 7 trillion math operations a second. Debate and cooperation The Japanese supercomputer underscores a continuing deb
24、ate within the computer design community. One camp has argued for building massively parallel supercomputers by chaining together thousands of off-the-shelf microprocessors. That philosophy has come to dominate designs in the United States in recent years. A second camp has pushed for computers made
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- 外语类 试卷 大学 英语四 模拟 238 答案 解析 DOC
