Maybe "remembering in long-term memory" means understanding, internalizing, and intuiting? I got the same problem as the author described when taking physical c

Maybe "remembering in long-term memory" means understanding, internalizing, and intuiting? I got the same problem as the author described when taking physical chemistry and linear algebra. All of sudden, there were so many concepts per page and the concepts were so abstract to use that my usual M.O of getting very good at derivation and proofs by manipulating equations stopped working. Only then did I realize that I needed explicitly focus on intuitively understanding each concept.