brush up / brush up on 是指需要反复练习以便加强提高技能和知识。这种表达常用在商业场合。

例如 You need to brush up on your skills。 你需要提高技能。
 

我需要提高一下我的西班牙语。I need to brush up my Spanish.

温习一下你的编程知识吧。 Brush up on your knowledge of programming.  

最后是一个主流媒体上用过的例句： Clearly Fox Business producers need to brush up on the hairstyles of meat-industry executives. 很明显，福克斯的制片人需要对肉类行业高管的发型有所了解。
(出处： Washington Post, "Activist posing as Smithfield CEO hoaxes Fox’s Maria Bartiromo," 23 Dec. 2020)