Brush up on (something)

Do you know the English expression “to brush up on (something)“? Read the conversation below. Can you guess the meaning?

Eva: Are you looking forward to your trip to Spain?

Harry: Yes, I’m really excited. But I need to brush up on my Spanish before I go. I haven’t used it for a few years.

Does it mean:

a) find something

b) brush something

c) start learning a skill

d) review a skill

The answer is below! ↓

 

Answer: d) review a skill