What were you taught but do not remember?
Awww...........oh wait man, I forgot my book.....man!
Any form of math I suppose. My achilles heel,
I had so much stuff crammed into my head during my years in the Marines that I've forgot at least half of it!
I can't remember what I don't remember.
How to play the clarinet. I was good enough for the school marching band many years ago, but I doubt if I could remember a single note today.
I forgot many things.