Memorized things are not the same as knowing something for language. I believe that they are stored in different parts of the brain. Possibly the "memory" for language has faster synapses. But what I found in my years of teaching was that memorized things were indeed in the brain but that they were "forgotten" when needed for langiage use.
Post some of the phrasal verbs that you'd like to learn to use and I'll show you what I mean.
Student or Learner