be somebody’s department
成語所屬單字department
be somebody’s department — 慣用語
1. This means that a particular area or topic is someone's responsibility or area o
1.慣用語
釋義
是某人的職責範圍
This means that a particular area or topic is someone's responsibility or area of expertise.
例句
If you need help with the computer, ask Maya; that's her department.
Why are you asking me about cooking? That's definitely not my department.