The age structure of Chinese sports population take on a distribution of "saddleshape", which showed that the ageing population (especially the female elderly) makes an important role in it.
根据研究表明，我国体育人口年龄结构呈现“马鞍型”分布，老年人口是体育人口的重要组成部分。
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The hyperbolic surface, which has so-called negative curvature because its surface curves up and down at the same time, like a saddle, just might represent the shape of the universe.