we 've seen the hippie-turned-yuppie plot before , 
(ROOT (S (NP (PRP we)) (VP (VBP 've) (VP (VBN seen) (NP (DT the) (NML (NML (NN hippie)) (HYPH -) (VP (VBN turned) (HYPH -) (ADJP (JJ yuppie)))) (NN plot)) (ADVP (RB before)))) (, ,)))
(ROOT (S (NP (PRP )) (VP (VBP ) (VP (VBN ) (NP (DT ) (NML (NML (NN )) (HYPH ) (VP (VBN ) (HYPH ) (ADJP (JJ )))) (NN )) (ADVP (RB )))) (, )))