Mercury Retrograde

I'm taking 2 classes right now, a swimming class and a Korean language class. My swimming class is called "gogeup," fourth level. On Friday, my teacher told me, and about half the class, that we need to retake it. Then in my intermediate Korean class today, my teacher told me I need to go back to the beginner class. This is so Mercury retrograde. This time rules words starting with -re. What do you have to redo now?