What ' s more , the lessons of statistics and probability could promote students " statistics ideas and probability thinking effectively . especially , there is only some research on compilation of statistics and probability in mathematics textbooks for elementary schools in foreign nations , and which is still on the inchoative stage in china 关于小学数学“统计与概率”的编写和实验研究在国内刚刚起步,国外相关研究也较少,可见本文的探索是富有新意的,且这一研究对我国正在进行的小学数学课程改革有一定的参考和借鉴价值。
2.
Along with development of mining in this region , abnormity of heavy - metal endogenetic geochemistry change to heavy - metal inchoative geochemistry , which lead to accumulation and diffusion of heavy metal in mine region of red soil and great red soil area , serious degradation of soil caused by heavy metal pollution , and mine ecological system destroy 随着有色金属采矿业的发展,重金属的内生地球化学异常转化向表生地球化学异常。由此,使红壤矿区土壤乃至大面积红壤中重金属积累扩散,造成土壤重金属污染退化加剧,生态系统遭受严重破坏。
3.
The fault controlled the magmatism and metallization relevant to the contact zone , and deformed successively and produced cataclastic rocks and two sets of joints ; the second stage was from late cretaceous to eocene . the fault zone deformed right - laterally under ne - sw striking transtention , and new joints zone was produced at the end of the two main faults because of local stress concentration . the fault produced inchoative cataclastic rocks , and two sets of typical joints in plutons ; the third stage of deformation was relatively faint and only a little of microcracks was produced and infilled with vei ns in the deformed rocks , which was during the himalayan movement 其后的继承性活动在断裂带内形成碎裂程度最强达到碎裂岩的碎裂岩系列构造岩,变形带两侧发育两组典型的共轭剪节理;第二次在晚白垩世?始新世,断裂在北东?南西向近水平挤压作用下右行张扭性活动,断裂带两主断裂在斜列重叠的端部由于局部应力集中进一步扩展形成节理带,而断裂在岩体区也发育两组典型的共轭剪节理,断裂内形成初碎裂岩为主的构造岩;第三次是喜山期以西侧抬升、东侧下降的强烈升降为主的活动,在基岩中,主断层两侧围岩出现微破裂。