Cách sử dụng
The expression "up and down" is used to describe a movement that goes in a vertical direction. For example, when you climb stairs, you are moving up and down. It can also be used to describe fluctuation or inconsistency in something. For instance, if someone's mood changes constantly in a short period, we can say they are up and down emotionally. This expression is commonly used in everyday conversations and can refer to a wide range of things from physical movement to emotional states.