About last year, I used to be able to listen to my teachers in class carefully, absorb it well, and then do well on quizzes/tests. But now, more into my junior year, I do pay attention and I understand how to do it, but then when it comes to quizzes and tests, I completely blank out and forget how to do it. Why has this happened to me? Before I was able to just study and know that I can solve a certain problem, but now, I completely forget how to do it? Why?