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《明斯克协定》
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第二篇 Video recorders and photocopiers, even ticket machines on the railways, often seem unnecessarily difficult to use. Last December I bought myself a video cassette recorder(VCR) described as "simple to use". In the first three weeks I failed repeatedly to program the machine to record from the TV, and after months of practice I still made mistakes. I am not alone. According to a survey last year by Ferguson, the British manufacturer, more than one in four VCR owners never use the timer(定时器) on their machines to record a programme: they don’ t use it because they’ve found it far too hard to operate. So why do manufacturers keep on designing and producing VCRs that are awkward to use if the problems are so obvious. First, the problem we notice are not obvious to technically minded (有技术思想的) designers with years o[ experience and trained to understand how appliances work. Secondly, designers tend to add one or two features at a time to each model, whereas you or I face all a machine’ features at once. Thirdly, although finding problems in a finished product is easy, it is too late by then to do anything about the design. Finally, if manufacturers can get away with selling products that are difficult to use, it is not worth the effort of any one of them to make improvements. Some manufacturers say they concentrate on providing a wide range of features rather than on making the machines easy to use. But that gives rise to the question, "Why can’t you have features that are easy to use" The answer is you can. Good design practice is a mixture of specific procedures and general principles. For a start, designers should build an original model of the machine and try it out on typical members of the public—not on colleagues in the development laboratory. Simple public trials would quickly reveal many design mistakes. In an ideal world, there would be some ways of controlling quality such as that the VCR must be redesigned repeatedly until, say, 90 per cent of users can work 90 per cent of the features correctly 90 per cent of the time. One of the reasons why VCRs are so difficult to use is that______.
以下程序计算自然数e的值，要求精确到1015，阅读下列程序。已知e的计算公式为：e=1+1/1!+1/2! + …+1/n!。请在 【6】 和 【7】 处填上正确内容。Private Sub Commandl_ Click() 【6】 n =0: term = 1: t = 1 do n= n +1 t=t/n 【7】 Loop while t ＞1.0E-15 Text1. Text = termEnd Sub
简答题 试对赫鲁晓夫改革进行评价。
阅读下面的短文，文中有15处空白，每处空白给出4个选项，请根据短文的内容从4个选项中选择1个最佳答案。 One of the most important technological developments during the 1980s has been the emergence of optical fiber communication as a major international industry. One indication of the (51) of this development is the total (52) of installed fiber, which was estimated to be 3.2 million kilometers in the U.S. alone by the end of 1987. Over 90% of this fiber was placed. (53) during the time period of 1982—1987. Long-haul trunk installations(长途干线设施) have dominated, (54) for about 95% of the fiber in the U.S. In the early 1950s the researchers who produced the first clad glass optical fibers were not (55) of using them. for communications. (56) , fiber optics was already a well-established commercial technology when the famous paper by Kao and Hockham, (57) the use of low-loss optical fibers for communication, appeared in 1966. The first low-loss silica fiber was described in a publication which appeared in October of 1970. The date of this publication is sometimes (58) as the beginning of the era of fiber communication. Although this development did receive (59) attention in the research community at- the time, it was far from inevitable that a major industry would evolve. The technological barriers appeared (60) because there were serious doubts as to (61) these fiber components could ever be produced economically enough, but the market potential was very significant. (62) , research and development activity expanded rapidly, and a number of important issues were (63) during the early 1970s. During the middle and late 1970s, the rate of progress towards marketable products accelerated as the emphasis (64) from research to engineering. Fibers with losses approaching the Payleigh limit of 2 dB/km at a wavelength of 0.8um were produced. By 1980 improvement in component performance, cost, and reliability led to major commitments (65) the part of telephone companies.
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