折线图说明了什么问题 A．1932年的工业产值比1929年下降了36.2亿美元

心肺复苏时，不应经气道给入的药是（）

A.Lidocaine

B.Atropine

C.Adrenaline

D.5%NaHCO₃

E.Dexamethasone

某传染病的最短潜伏期为8天，最长潜伏期为22天，平均潜伏期为14天，症状期为21天，恢复期为30天。请问该病的检疫期限为（）

A、8天

B、22天

C、14天

D、21天

E、30天

计算机通常用MB（兆字节）作为主存容量的计量单位，这里1MB等于（）字节。

A.210

B.220

C.230

D.106

Many people are concerned about the economic condition of developing countries — countries whose average per capita GNP is a fraction of that in more industrialized countries. However, for the developing countries, there exist many obstacles to their economic development.
One major obstacle to economic development is population growth. (46) The populations of most developing countries grow at a rate much faster than those of industrialized countries, and the population of some of them is so large that there is barely enough fertile land and other resources to support it. Many less developed countries depend extensively on agriculture, adding to the problem. In these countries, an incentive to have many children exists. (47) Most farms are worked by families, and children can work in the fields at an early age because most farmers believe that more children means more workers. In addition, having many children ensures the parents that someone will look after them in their old age.
Another problem for developing countries is increasing average life expectancy—the average remaining lifetime for persons who reach a certain age. Better education, international aid, and emphasis on health-care facilities help people live longer. A high life expectancy coupled with a high crude birthrate makes it difficult to increase per capita GNP.
Another obstacle to economic growth is limited natural resources. No country can develop beyond its resource potential. Unproductive land or a harsh climate can limit economic growth. (48) Some countries may be fortunate enough to discover a valuable mineral to finance their economic development, but most focus on agriculture and, as a result, their economic growth is hindered by the shortage of natural resources or energy sources needed for industry.
Still another obstacle to economic development is a lack of appropriate education and technology. Any developing countries do not have a highly literate population or the high level of technical skills needed to build an industrial society. In addition, most do not have money to train engineers and scientists. (49) Many developing countries cannot even afford to provide free public education for school-age children, and in those that can, not every child is able to take advantage of it because most of them have to work to help feed their families. As a result, much of the population may not have the basic skills needed to continue with higher education when it is offered.
Government also can be an obstacle to economic development. A country whose government often changes will have a hard time developing economically. Such constant changes impede long-term planning. (50) Economic development is made even more difficult if the political changes occur through violent revolution where industrial facilities may be destroyed.

作品的（）问题是著作权法的核心问题。

A、固定性

B、原创性

C、独创性

D、可传播性