This article gives an easy way in which laser plumb line is set up by means of He-Ne laser in space with the liquid level as the base.

本文叙述以液面为基准面，用小型氦-氖激光器在空间建立激光垂直线的简易方法。

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I spent all day at the construction site, from sunrise to sunset, using my 2 level to make sure the walls were even and my 3 plumb line to check that they were standing straight.

摩顿森说，“我整天待在工地，从早忙到晚，用水平线确定墙砌得够平，用铅垂线量它们够不够直。”

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