crews 和 staff 和 personal 的差別在哪裡？如果不好說明，請提供一些例句。

"Personnel", not "personal".
They all mean the same as "employee".
Staff is generally a term for one or all of your employees.
A crew is a team of employees.
Personnel would usually be a group of employees with authority or an official status (maybe a group of uniformed employees or employees with certain security clearance).
All of those terms are fine though. Use "staff" if you're not sure.