So, what's it about? The main point is that I do ever memorized that poem when I was a child. I knew that. But I can't recall that poem at all now. Actually, the poems I can recite now are only a few and are all very short. The poem in my dream, however, is very long so I am assured that it's not the kind of poems I can recite when I am awake.
It's pretty interesting that I find my brain working in such a strange way that I remember more things when I am asleep than I am awake. It seems that my brain locked some of my memory somewhere in daytime and release them having party in my dream at night.
My friends Matt told me that it's actually how our brains work. In fact, our brains remember much more things than we are aware of. That's why we can construct such a vivid scene in our dream because our brain already memorize a lot of details in advance for us. Brains just save them somewhere and lock them.
The question is why brains do that locking thing. In my opinion, it's because that brain would work more efficiently that way. Just imagine our brains as computers with a data base. If we don't lock some not-so-important data, the data base would be so large that it would cost vast amount of time to search files. I think our brian will lock some memory from use especially for the memory that is not used for a long time. In this way, our brain can keep the system working faster and faster.