(S (S (BASENP (DT The) (NNS authors)) (VP (VP (VBD drew) (BASENP (PRPD their) (NNS conclusions))) (PP (IN from) (NP (BASENP (DT a) (NN model)) (PP (IN of) (NP (BASENP (DT the) (NN dynamics)) (PP (IN of) (BASENP (NN antibody) (NN evolution))))))))) (PERIOD .))