If a man merely watches the limits of time and space, he will never step over the boundary of the paradigm of life.

如果一个人只看时间和空间的界限，他永远也不能跨越生命的框框的边界。

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The ignition process of combustible gas stream by a heated plate in the laminar boundary layer was analytically considered and the limits of ignition were determined.

以此分析了炽热平板层流边界层内可燃气流的引燃，给出了描述引燃的着火临界条件。

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This limits the dangers of operating in old workings, he said, and creates a boundary between the old and new collieries.

BBC: Gleision Colliery near Cilybebyll: Brief history