Cách sử dụng
The expression "what's what" means to understand something fully or to know the important facts about a situation. It is often used in informal and casual situations. For example, if someone is new at a job, they may ask a colleague to explain "what's what" in the office, meaning they want to know the important details and rules they need to be aware of. Similarly, if someone is describing a situation to a friend, they may say "let me tell you what's what" to give a clear understanding of what happened.