Conversely, I retain almost nothing I get from books. But if you can explain something so I actually understand it, I don't even need to revise come exam time.

Conversely, I retain almost nothing I get from books. But if you can explain something so I actually understand it, I don't even need to revise come exam time. If I understand it, or at least well enough to reconstruct a complete understanding on the fly, then I'll ace the exam. If you expect me to try and learn it from a book, I'll still do okay, but it'll take me 10 times longer to learn it.