(S (S (BASENP (NNS Volunteers)) (VP (VP (VBD spent) (BASENP (JJ last) (NN night))) (S (VP (VP (VBG reviewing) (BASENP (DT the) (VBN submitted) (NNS petitions))) (CC and) (VP (VBG validating) (BASENP (NNS signatures))))))) (PERIOD .))