Cách sử dụng
The expression "on/off the radar screen" means whether someone or something is noticeable or not. It comes from the idea of a radar system which detects objects in the sky, so if something is on the radar screen, it can be seen and detected, but if it's off the radar screen, it cannot be seen or detected. This expression can be used in different situations, such as in a conversation about a person who is not showing up or being active in a particular group, or a problem that is not being addressed. For example, "He used to come to all our meetings, but lately he's been off the radar screen" means that he's not been around, and his absence is noticeable.