Cách sử dụng
The word 'complain' means to express dissatisfaction or unhappiness about something. It is used when you are unhappy about a situation or a thing and you want to let other people know about it. For example, if you have received bad service at a restaurant, you might complain to the manager to try to make them aware of the problem and get it resolved. It is important to complain when something is not right, so that things can be corrected and you can feel satisfied again. However, it is also important to be polite and respectful when complaining.