a practical farmer的用法和样例：
- It can refer to an academic subject or a practical skill.
- He has a practical partner who organizes everything for him.
- This book is too theoretical; I need a practical one.
- I favor as a practical policy the putting of first things first.
- The children put salt in the sugar bowl as a practical joke.
- He put a shovelful of snow in Kate's bed as a practical joke.