( ( Sound waves ) ( ( ( lose energy ) ( as ( they travel ) ) ) . ) )
(ROOT (S (NP (JJ Sound) (NNS waves)) (VP (VBP lose) (NP (NN energy)) (SBAR (IN as) (S (NP (PRP they)) (VP (VBP travel))))) (. .)))
Sound waves lose energy as they travel.
(ROOT (S (NP (JJ Sound) (NN energy)) (VP (VBZ travels) (PP (IN through) (NP (NP (NN matter)) (PP (IN in) (NP (NN wave) (NN form)))))) (. .)))