Cách sử dụng
The word 'undercover' is used to describe when someone is secretly working or pretending to be someone else. This can happen in many different situations, such as police officers who go undercover to catch criminals, journalists who pose as someone else to get a story, or spies who work for a government and try to blend in with a group of people to gather information. When you use the word 'undercover', it means that someone is not revealing their true identity, and they are trying to act like someone else for a specific purpose.