双曲表面，即通常所称的负曲率，因为它的表面曲线同时有的向上和有的向下，像一个马鞍，也许这样就可以代表宇宙的形状。

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.

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中国国际问题研究所所长曲星、俄罗斯驻华大使拉佐夫，以及约70位中俄外交界、学术界、新闻界代表与会。

There were about 70 participants including CIIS President Qu Xing, Russia's Ambassador to China Sergey Razov, and representatives from diplomatic, academic, and media circles of the two countries.

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贝多芬创作的五部大提琴与钢琴奏鸣曲代表了其一生创作的三个精华阶段。

Beethoven's five sonatas for cello and piano represent his three major creative periods.

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