Cách sử dụng
The phrase "run in" means to use or wear something for a short period of time to make sure it works properly or feels comfortable. For example, you might want to run in a new pair of shoes before wearing them all day to make sure they don't hurt your feet. Additionally, the phrase can be used to describe a period of time when a car or machine needs to be driven gently and carefully to make sure it works smoothly. In general, "run in" is used to describe a short amount of time where you test something out before fully committing to it.