n. a person who rules or commands
n. 统治者, 管理者, 尺, 直尺
n. 划线板
[计] 标尺
1. She used a ruler to draw a straight line.
她用尺子画了一条直线。
2. The teacher asked the students to measure the paper with a ruler.
老师让学生用尺子测量纸张。
3. I always keep a ruler in my pencil case for school.
我总是在文具盒里放一把尺子以备学校使用。