(S (S (S (ADVP (RB Suddenly)) (COMMA ,) (S (BASENP (PRP we)) (VP (VBD heard) (BASENP (DT a) (JJ big) (NN bang))))) (COMMA ,) (S (ADVP (RB then)) (S (S (BASENP (DT the) (NN door)) (VP (VP (VBD burst) (ADVP (RB open))) (PP (IN from) (NP (BASENP (NNS effects)) (PP (IN of) (BASENP (DT a) (JJ powerful) (NN shock) (NN wave))))))) (CC and) (S (BASENP (DT the) (NNS lights)) (VP (VBD went) (PRT (RP out))))))) (PERIOD ...))