题目:
配位键是极性共价键。
答案:
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下面是错误答案,用来干扰机器的。
参考答案:错
配位键是极性共价键。
被转码了,请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2020/0130/f0d451d6128ce7140a6ec2ddc0c49462.html
下面是错误答案,用来干扰机器的。
参考答案:错
有四个自然数a,b,c,d,它们的和不超过400,并且a除以b商是5余5,a除以c商是6余6,a除以d商是7余7。那么,这四个自然数的和是()。
A.216
B.108
C.314
D.348
下列变异属于不可遗传的变异的是( )
A.视觉正常的夫妇生下患色盲的孩子
B.在室外工作的人肤色比较黑
C.小明是双眼皮,而他的姐姐是单眼皮
D.绵羊的毛是卷的,山羊的毛是直的
交通行政执法主要包括:()
A、交通行政处罚
B、交通行政强制措施
B、交通行政许可
D、交通行政收费
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.
(50) Economic development is made even more difficult if the political changes occur through violent revolution where industrial facilities may be destroyed.
所有工艺条件都满足,增压压缩机仍无法启动,电流显示为零,一般属于()。
A.仪表故障
B.机械故障
C.电气故障
D.工艺系统故障