This is my old friend, Monsieur Poirot, whom I have not seen for years."
( This ( ( ( is ( ( ( ( ( my ( old friend ) ) , ) ( Monsieur Poirot ) ) , ) ( whom ( I ( ( have not ) ( seen ( for years ) ) ) ) ) ) ) . ) '' ) )
(ROOT (S (NP (DT This)) (VP (VBZ is) (NP (NP (PRP$ my) (JJ old) (NN friend)) (, ,) (NP (NNP Monsieur) (NNP Poirot)) (, ,) (SBAR (WHNP (WP whom)) (S (NP (PRP I)) (VP (VBP have) (RB not) (VP (VBN seen) (PP (IN for) (NP (NNS years))))))))) (. .) ('' '')))
I haven't seen this old friend in over a year. 
( I ( ( ( have n't ) ( ( seen ( this ( old friend ) ) ) ( in ( over ( a year ) ) ) ) ) . ) )
(ROOT (S (NP (PRP I)) (VP (VBP have) (RB n't) (VP (VBN seen) (NP (DT this) (JJ old) (NN friend)) (PP (IN in) (PP (IN over) (NP (DT a) (NN year)))))) (. .)))