by rule of thumb

• 凭经验

by rule of thumb的用法和样例：

例句

1. They learn to cook by experience.
   都是凭经验做的。
2. But he never missed my breakfast and dinner, knowing by experience that he fared best there.
   但是它从来都不会错过我的早餐和午餐，凭经验它知道在我这儿吃得最好。