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