(S (S (S (BASENP (DT A) (JJ large) (NNS police) (NN presence)) (VP (VBD watched) (PP (IN over) (BASENP (DT the) (NNS scenes))))) (SBAR (IN as) (S (BASENP (NNS mourners)) (VP (VBD wept))))) (PERIOD .))