(S (S (PP (IN After) (BASENP (DT the) (NN meeting))) (COMMA ,) (S (BASENP (NNP Biden)) (VP (VP (VP (VBD sent) (BASENP (DT a) (JJ follow-up) (NN letter))) (PP (TO to) (BASENP (DT the) (NNP White) (NNP House)))) (S (VP (VBG asking) (PP (IN for) (NP (NP (BASENP (DT an) (NN explanation)) (PP (IN from) (BASENP (DT the) (NNP Bush) (NNP Administration)))) (PP (IN on) (BASENP (DT the) (NN matter)))))))))) (PERIOD .))