rule of thumb片语

经验法则、大致准则

A good rule of thumb is to drink water before every meal.

一个实用的经验法则是每餐前先喝水。

粗略估算、约略的算法

As a rule of thumb, allow two hours for the drive.

粗略估算，开车要预留两小时。

粗略的、凭经验的

Her rule-of-thumb estimate turned out to be surprisingly accurate.

她那个粗略的估算结果竟然相当准确。