通过变异操作,使遗传算法具有局部的随机搜索能力。对此,下列说法不正确的是( ) A、当产生一个可行解时,可以在……

未分类题The passage suggests that the purpose of the 'hydrographic network' is to ______.A.determine the size of molecules of waterB.prevent soil erosion caused by floodingC.move water from the Earth's surface to the oceansD.regulate the rate of water flow from streams and rivers

单项选择题老年人保证充足的维生素E供给量是为了 ( )A. 抗疲劳 B. 增进食欲C. 增强机体的抗氧化功能D. 降低胆固醇

未分类题People in the United States in the nineteenth century were haunted by the prospect that unprecedented change in the nation's economy would bring social chaos. In the years following 1820, after several decades of relative stability, the economy entered a period of sustained and extremely rapid growth that continued to the end of the nineteenth century. Accompanying that growth was a structural change that featured increasing economic diversification and a gradual shift in the nation's labor force from agriculture to manufacturing and other nonagricultural pursuits.Although the birth rate continued to decline from its high level of the eighteenth and early nineteenth century, the population roughly doubled every generation during the rest of the nineteenth century. As the population grew, its makeup also changeD.Massive waves of immigration brought new ethnic groups into the country. Geographic and social mobility-- downward as well as upward--touched almost everyonE.Local studies indicate that nearly three-quitters of the population--in the North and South, in the emerging cities of the Northeast, and in the restless rural counties of the West--changed their residence of the Northeast, and in the restless rural counties of the West--changed their residence each decadE.As a consequence, historian David Donald has written, 'Social atomization affected every segment of society,' and it seemed to many people that 'all the recognized values of orderly civilization were gradually being erodeD.'Rapid industrialization and increased geographic mobility in the nineteenth century had special implications for women because these changes tended to magnify social distinctions. As the roles men and women played in society became more rigidly defined, so did the roles they played in the homE.In the context of extreme competitiveness and dizzying social change, the household lost many of its earlier functions and the home came to serve as a haven of tranquility and order. As the size of families decreased, the roles of husband and wife became more clearly differentiated than ever beforE.In the middle class especially, men participated in the productive economy while women ruled the home and served as the custodians of civility and culturE.The intimacy of marriage that was common in earlier periods was rent, and a gulf that at times seemed unbridgeable was created between husbands and wives.What does the passage mainly discuss?A.The economic development of the United States in the eighteenth century.B.Ways in which economic development led to social changes in the United States.C.Population growth in the western United States.D.The increasing availability of industrial jobs for women in the United States.

未分类题The Second role Kim is playing is that of responsible leader.A.YB.NC.NG

未分类题Kim won the 2000 Nobel Peace Prize for his contribution to inter-Korean detentE.A.YB.NC.NG