While at the playground, Max and Ruby take it in turns to give each other a push on the swings.

在游乐场，马克思和卢比还会轮流相互帮对方推秋千。

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This paper simply introduces a ruby laser with max. relative error of output energy< 2% and it's features about construction.

本文简介一种输出能量最大相对误差小于2％的红宝石激光器及其结构特点。

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