(S (S (BASENP (PRP It)) (VP (VBZ is) (NP (BASENP (DT the) (JJ fourth) (NN ship)) (SBAR (S (VP (TO to) (VP (VB be) (VP (VBN attacked) (PP (IN in) (NP (BASENP (DT the) (NN space)) (PP (IN of) (BASENP (DT a) (NN week))))))))))))) (PERIOD .))