(S (S (BASENP (DT The) (JJ vigorous) (NNS tests)) (VP (VBP are) (VP (VBN thought) (S (VP (TO to) (VP (VB be) (NP (BASENP (DT the) (JJ first)) (PP (IN of) (BASENP (PRPD their) (NN kind)))))))))) (PERIOD .))