moved to the edge of their seats by the dynamic first act 
(ROOT (S (VP (VBD moved) (PP (IN to) (NP (NP (DT the) (NN edge)) (PP (IN of) (NP (PRP$ their) (NNS seats))))) (PP (IN by) (NP (DT the) (JJ dynamic) (JJ first) (NN act))))))
(ROOT (S (VP (VBD ) (PP (IN ) (NP (NP (DT ) (NN )) (PP (IN ) (NP (PRP$ ) (NNS ))))) (PP (IN ) (NP (DT ) (JJ ) (JJ ) (NN ))))))