Cách sử dụng
The phrase "sit in on" means to attend a meeting, class, or event as an observer without participating actively. For example, if you are not a student of a particular class, but you want to observe the lesson, you can ask the teacher if you can sit in on it. Similarly, if you want to attend a board meeting at your office, you can ask your boss if you can sit in on it. It is a way of experiencing something without actively taking part in it.