( ( ( Only the ) ( on behavior ) ) ( ( is described ) . ) )
(ROOT (S (NP (NP (RB Only) (DT the)) (PP (IN on) (NP (NN behavior)))) (VP (VBZ is) (VP (VBN described))) (. .)))
Only the on behavior is described.
(ROOT (S (NP (JJ Learned) (NN behavior)) (VP (VP (VBZ occurs) (ADVP (RB only)) (PP (IN after) (NP (NN experience) (CC or) (NN practice)))) (CC and) (VP (VBZ describes) (NP (RBS most) (JJ human) (NNS behaviors)))) (. .)))