( Wind ( ( can ( be ( ( defined simply ) ( as ( air ( in motion ) ) ) ) ) ) . ) )
(ROOT (S (NP (NN Wind)) (VP (MD can) (VP (VB be) (VP (VBN defined) (ADVP (RB simply)) (PP (IN as) (NP (NP (NN air)) (PP (IN in) (NP (NN motion)))))))) (. .)))
Wind can                         be defined simply as air in motion.
(ROOT (S (NP (NNP Motion)) (VP (MD can) (VP (VB be) (VP (VBN defined) (ADVP (RB simply)) (PP (IN as) (NP (NP (DT a) (NN change)) (PP (IN in) (NP (NN position)))))))) (. .)))