(S (S (PP (IN On) (BASENP (NNP Wednesday))) (COMMA ,) (S (BASENP (NNP Robertson)) (VP (VBD sent) (NP (NP (BASENP (DT a) (NN letter)) (VP (VBN addressed) (PP (TO to) (NP (NP (BASENP (NNP Sharon) (POS 's)) (NN son)) (NNP Omri))))) (VP (VBN apologizing) (PP (IN for) (BASENP (PRPD his) (NNS comments)))))))) (PERIOD .))