hand rule

例句：

1. 1. He decided to use his hand rule to measure the length of the wall.
   他决定用手边的规则来测量墙的长度。
2. 2.The teacher taught us to use our hand rules when we were learning a new language.
   老师教我们使用手边的规则来学习一门新语言。
3. 3. It's important to follow the hand rule of safety when working with chemicals.
   在处理化学品时，遵循安全的手边规则很重要。