This paper briefly summarizes all the kinds of the environmental disasters in the area, and analyses the genetic relation between the primary and secondary disasters.
简要总结了各种煤矿环境地质灾害，分析了原生灾害及其次生灾害的成生联系。
But, present researches cast little light on interior relation of primary, secondary and tertiary industries and relation of industrial structure and space structure, employment structure.
但目前的研究在一二三产业内部结构和产业结构与空间结构、就业结构的相互关系方面仍较为薄弱。
The purpose of this study is to probe into the extent of preparation for self-directed learning of primary and secondary teachers and its relation with learning effect.
本研究旨在探讨中小学教师的自我导向学习准备度及其与学习成效的关系。
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