(S (S (PP (IN At) (NP (BASENP (DT the) (JJ five-year) (NN study) (POS 's)) (NN conclusion))) (S (BASENP (DT the) (NNS participants)) (VP (VBD were) (ADJP (JJ aged) (NP (QP (BASENP (NN 17)) (PP (TO --) (BASENP (NN 23))))))))) (PERIOD .))