复数： rulers

Did tribes voluntarily delegate authority to a powerful ruler ?

部落会自愿将权力转交给强大的统治者吗？

The hereditary ruler as hero

如英雄般世袭的管理者

The type of laser used to make the comb is critical to the precision of the ruler .

用来产生光学频率梳的激光的类型对于此频率尺的精度至关重要。

In the case of this book , the tools we will be using are a compass and a ruler .

在本书中，我们将使用的工具是圆规和直尺。

A great firefox plugin that lets you draw out a ruler to get the pixel width and height of any elements on a webpage .

很棒的firefox插件，绘出一把尺子获得任何内容网页上像素的宽度和高度。