Cách sử dụng
The word 'sir' is a polite way to address a man. You can use it when speaking to a stranger or someone in a position of authority, such as a teacher or boss. For example, if you are in a store and need assistance, you can say "Excuse me, sir, could you help me?" It is also common to use 'sir' when answering a question or responding to a request made by someone with authority. However, it is not necessary to use 'sir' when speaking to friends or family members.