been gathering dust on mgm 's shelf 
(ROOT (S (NP (VBN been)) (VP (VBG gathering) (NP (NN dust)) (PP (IN on) (NP (NP (NNP mgm) (POS 's)) (NN shelf))))))
(ROOT (S (NP (VBN )) (VP (VBG ) (NP (NN )) (PP (IN ) (NP (NP (NNP ) (POS )) (NN ))))))