Cách sử dụng
When someone says "listen in" it means that you are being invited to listen to a conversation or discussion that is already going on. It is usually used when there are multiple people involved in the conversation and someone wants to ask others to join and pay attention. For example, if a group of people are talking and someone wants to make sure another person is paying attention, they might say "Hey, can you listen in on this conversation?" It is often used in a casual, friendly way.