a diploma mill的用法和样例：
- The college was nothing more than a diploma mill.
- You won't get a good job if you graduate from a diploma mill like that.
- Some of you have probably never heard of a diploma mill, and some of you probably have, and hopefully, have not gotten taken by one.
- He obtained a diploma in architecture.
- A diploma is no guarantee of efficiency.
- She gained a diploma in Business Administration.