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. The people who are surprised are so because they have assumed that ______.
A. there is a positive correlation between the two variables.
B. the higher the per capita income the lower the population density.
C. the greater the number of people the greater the per capita income.
D. the relationship between the variables is statistically insignificant.
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
A. 如果一个公司没有采用略有不同的计算机操作系统,它将会由于病毒的损害而失去所有的数据。
B. 如果计算机病毒侵入一台商用计算机,这台计算机的所有数据都会丢失。
C. 如果一个公司在其网络中采用略有不同的计算机操作系统,它将会提高对其网络的整体保护,但不能保证每一台计算机都不受病毒侵入。
D. 如果略有不同的计算机操作系统被使用,则使用这种软件的计算机中的数据就会更容易被获取。
E. 现存的商用计算机并非都采用完全相同的系统软件,计算机病毒的存在是难以避免的,只要有足够好的防毒软件即可。