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计算机的操作系统软件正在日益标准化。大量具有各种用途的商用计算机就被连接为一个网络，所有的计算机都使用完全相同的操作系统软件。当一个黑客侵入一台计算机时，便能自动进入网络中的所有计算机，并使用一种称做“病毒”的程序摧毁所有计算机上的数据。如果一个公司能开发出一种操作系统之间略有不同的软件，就可以避免黑客在同一时刻非法侵入所有的计算机，而且这种不同对商用计算机的兼容性不会产生任何影响。因此，有公司来完成这样的操作系统是明智的。 以下哪项可以从上述陈述中推出
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On your answer sheet, circle and black out the letter that best answers the questions below.Passage One Obviously, the per capita income of a country depends on many things, and any statistical test that does not take account of all important determinants is misspecified, and thus must be used only for descriptive and heuristic purposes. It is nonetheless interesting--and for many people surprising--to find that there is a positive and even a statistically significant relationship between these two variables: the greater the number of people per square kilometer the higher the per capita income. The law of diminishing returns is not invariably true. It would be absurd to suppose that a larger endowment of land ipso facto makes a country poorer. This consideration by itself would, of course, call for a negative sign on population density. Thus, it is interesting to ask what might account for the "wrong" sign and think of what statistical tests should ultimately be done. Clearly there is a simultaneous two-way relationship between population density and per capita income; the level of per capita income affects population growth just as population, by increasing the labor force, affects per capita income. The argument offered here suggests that perhaps countries with better economic policies and institutions come to have higher per capita incomes than countries with inferior policies and institutions, and that these higher incomes bring about a higher population growth through more immigration and lower death raters. In this way, the effects of better institutions and policies in raising per capita income swamps the tendency of diminishing returns to labor to reduce it. This hypothesis may also explain why many empirical studies have not been able to show a negative association between the rate of population growth and increases in per capita income. One reason why the ratio of natural resources to population does not account for variations in per capita income is that most economic activity can now readily be separated from deposits of raw material and arable land. Over time, transportation technologies have certainly improved, and products that have a high value in relation to their weight, such as most services and manufactured goods like computers and airplanes, may have become more important. The Silicon Valley is not important for the manufacturing of computers because of the deposits of silicon, and London and Zurich are not great banking centers because of fertile land. Even casual observation suggests that most modem manufacturing and service exports are not closely related to natural resources. Western Europe does not now have a high ratio of natural resources to population, but it is very important in the export of manufactures and services. In a parallel way, the striking success of Japan, Hong Kong, and Singapore, with relatively few natural resources per capita, cannot be explained by reliance thereon. Which of the following statements is true
著名认知心理学家安德森认为，心智技能的形成需经过三个阶段，即______、______、自动化阶段。
During the last few years, there has been an (36) increase in the number of shops, stores and supermarkets which provide (37) for serf-service. Their general purpose is to provide goods of every (38) attractively and cleanly and in perfect condition, so that the customer earl serve herself, and then pay for the goods with the least (39) . The organizers of a self-service store have their difficulties. They must display a great number of goods in a (40) space without covering up anything. They must deal with (41) foodstuffs requiting different ranges of temperature; and they must arrange a (42) flow of customers past the cash registers without (43) the operators. (44) , rotating circular shelves, islands of display stands, racks for tubed foods, and multi-tiered mobile stalls, (45) . These are at zero Fahrenheit for frozen food, 28-32 degrees for meat and fish, and 40-50 degrees for dairy produce and provisions. Some of the advantages of self-service seem to be that there is no waiting to be served; there is a wide variety of choice, and it is claimed that prepacked meat and vegetables are hygienic. Shopping is said to be more "stream-dined" and more economical. (46) .
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