The great power of this principle of selection is not hypothetical.

这种选择原则的强大力量并非假设。

The principle of selection I find distinctly given in an ancient Chinese encyclopaedia.

我发现中国古代百科全书中清楚地给出了选择原则。

It is an announcement that they have no guiding principles in their educational practice, no principles of selection in their arrangement of studies, no genuine grasp of the relationship between knowledge and life.

宣告他们在教育实践中没有指导原则，在学习安排上没有选择原则，没有真正把握知识与生活的关系。