Study carefully its origin, can roughly trace back to primitive human era. But the concept of informal group is put forward by modern management educational circles correspondent to formal group.

究其起源，大致可追溯到原始人类的时代，而非正式群体这一概念却是现代管理学界相对应于正式群体提出来的。

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Deriving the smallest primitive unit cells, necessary to describe the translational periodicity of a crystal structure, is the first step toward choosing the correct space group.

导出反映晶体结构周期的最小素单胞是正确判断空间群的第一步，其中以还原单胞的选择最为理想。

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Results The recovery time of muscle tension, primitive reflex and normal sense was significantly lower in the trial group than in the control group (P<0.05).

结果实验组肌张力、原始反射、意识状态恢复的时间明显少于对照组。

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This was a much more primitive, not-so-well organized group which we disrupted in any case.

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