(S (S (NP (BASENP (DT The) (JJ first) (NN flotilla)) (SBAR (S (VP (TO to) (VP (VB challenge) (BASENP (DT the) (NN blockade))))))) (VP (VBD was) (VP (VP (VBN stopped) (PP (IN by) (BASENP (JJ Israeli) (JJ naval) (NNS commandos)))) (PP (IN in) (NP (BASENP (NNP May)) (BASENP (DT this) (NN year))))))) (PERIOD .))