adduction of thumb的用法和样例：
- The rule of thumb in this business is courtesy.
- A teacher's most basic rule of thumb is: be patient.
- I never weigh anything when I'm cooking.I just do it by rule of thumb.
- I never weigh anything when I'm cooking-I just do it by rule of thumb.
- We aim for 80% contrast as a general rule of thumb.
- He can detect a typhoon by rule of thumb.