In class writing

In my opinion I think the three liars are ghost, in the book, when cadence in beachwood island .she saw them again, and the three liars always talk something to her and let her remember, and when cadence find back her memory,  they are still here, and say goodby to her, if they are cadence's imagination, I don't think cadence can remember what was happened in summer 15, and they can stay with cadence forever, but they leave cadence, and they can't stay too much time.