Why, when I was your age, I already had...."  Dave wasn't listening any longer.
( Why ( , ( ( ( ( ( ( when ( I ( was ( your age ) ) ) ) ( , ( I ( already had ) ) ) ) ... ) '' ) ( Dave ( ( was n't ) ( listening ( any longer ) ) ) ) ) . ) ) )
(ROOT (S (ADVP (WRB Why)) (, ,) (S (SBAR (WHADVP (WRB when)) (S (NP (PRP I)) (VP (VBD was) (NP (PRP$ your) (NN age))))) (, ,) (NP (PRP I)) (ADVP (RB already)) (VP (VBD had))) (: ...) ('' '') (S (NP (NNP Dave)) (VP (VBD was) (RB n't) (VP (VBG listening) (ADVP (DT any) (RBR longer))))) (. .)))
Dave didn't want to hear the conversation. 
( Dave ( ( ( did n't ) ( want ( to ( hear ( the conversation ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Dave)) (VP (VBD did) (RB n't) (VP (VB want) (S (VP (TO to) (VP (VB hear) (NP (DT the) (NN conversation))))))) (. .)))