The urban sustainable development occupies an important place in the national sustainable development . big and medium - sized city have many advantages in sustainable development , such as history tradition , geographical position , etc . they have stronger condense power , faster development speed , higher profit . in addition , they accord with the economic regular that optimum distribution of resources 大中城市的发展占有历史传统、地理区位、人文素质等方面优势，在客观上具有比小城市更强的凝聚力与内在冲动，发展的速度更快、效益更高，更符合资源最优配置的经济规律。
When proceed from the origin of the theory of the human resource , the concept of the explore of human resource . we can learn that the explore of human resource is an essential condition to the development of economy which can be stricted by its quantity and quality 本文从人力资源开发的内涵入手，得出人力资源开发是经济发展的根本保证，人力资源开发的水平影响着经济发展的速度和水平。西北地区人口众多，人力资源是西北地区最大优势、最大潜力所在，同时也是制约西北地区经济发展的最大瓶颈。
The plastic pipe industry in china is facing with the historical opportunities of big development . it is forecast that domestic production of plastic pipe will grow fast within the first decade in 21 century . the basis of the forecast lies in ( 1 ) the establishment of the foundation of the industry , ( 2 ) obvious expanding of market needs , ( 3 ) development contineously pushed forward by the progress of the technology . the developing rate in future and several of the most hopeful opportunities are forecast on the analysis of domestic development of plastic pipe in the past decade and the applications in each market of the scope 我国塑料管产业正面临大发展的历史机遇，预测在21世纪初的10年内中国塑料管产业将有一个较快的增长；预测的根据是：产业的基础已经建立，市场的需求明显扩大，技术的进步在不断地推动；分析过去10年我国塑料管的发展和在各个市场领域的应用情况；预测今后发展的速度和最有希望的几个机遇。
According to aforementioned analysis , chapter six draws four conclusions , that is : the post telecommunications industry is main industry and bottleneck industry and whose development speed is a bit low and in fact , whose price - deceasing spread most to the secondary industry , but spread little to the primary and the tertiary industry 在上述分析的基础上，第六章得出四个结论，邮电业是主导产业；邮电业属于瓶颈产业；邮电业发展的速度偏低；实践上，邮电业价格下降，对第二产业的价格波及最强，而对第一产业、第三产业的价格波及不明显。
