being trapped at a bad rock concert 
(ROOT (S (VP (VBG being) (VP (VBN trapped) (PP (IN at) (NP (DT a) (JJ bad) (NN rock) (NN concert)))))))
(ROOT (S (VP (VBG ) (VP (VBN ) (PP (IN ) (NP (DT ) (JJ ) (NN ) (NN )))))))