(S (S (ADVP (RB However)) (COMMA ,) (S (BASENP (NN co-star) (NNP Paul) (NNP Whitehouse)) (VP (VBD claimed) (SBAR (S (BASENP (PRP he)) (VP (VBD had) (NP (BASENP (DT no) (NN knowledge)) (PP (IN of) (BASENP (DT this) (NN research)))))))))) (PERIOD .))