an instance of an old dog not only learning but inventing a remarkable new trick . 
(ROOT (NP (NP (DT an) (NN instance)) (PP (IN of) (S (NP (DT an) (JJ old) (NN dog)) (VP (CONJP (RB not) (RB only)) (VP (NN learning) (CC but) (VBG inventing) (NP (DT a) (JJ remarkable) (JJ new) (NN trick)))))) (. .)))
(ROOT (NP (NP (DT ) (NN )) (PP (IN ) (S (NP (DT ) (JJ ) (NN )) (VP (CONJP (RB ) (RB )) (VP (NN ) (CC ) (VBG ) (NP (DT ) (JJ ) (JJ ) (NN )))))) (. )))