(S (S (NP (BASENP (JJ Previous) (NNS attempts)) (S (VP (TO to) (VP (VB negotiate) (NP (BASENP (DT an) (NN agreement)) (PP (IN between) (BASENP (DT the) (NN two) (JJ Palestinian) (NNS groups)))))))) (VP (VBP have) (VP (VBN ended) (PP (IN in) (NP (BASENP (NN cease) (NN -) (NN fire)) (SBAR (WHNP (WDT that)) (S (VP (VBP have) (VP (VBN lasted) (BASENP (RB only) (DT a) (JJ short) (NN time))))))))))) (PERIOD .))