Cách sử dụng
The expression "knuckle down" means to start working on something seriously and with determination. It is often used when someone needs to focus and concentrate more on a task or project. For example, if you have a big exam coming up, you might need to "knuckle down" and study hard to do well. Or, if you have a lot of work to do at your job, you might need to "knuckle down" and focus on getting it all done efficiently. So, if someone tells you to "knuckle down," it means they want you to take your work more seriously and put in the effort to do it well.