( ( Potential energy ) ( ( stored ( energy 2 ) ) . ) )
(ROOT (S (NP (JJ Potential) (NN energy)) (VP (VBD stored) (NP (NN energy) (CD 2))) (. .)))
Potential energy stored energy 2.
(ROOT (S (NP (NP (DT The) (NN energy)) (SBAR (WHNP (WDT that)) (S (VP (VBZ is) (VP (VBN stored) (PP (IN in) (NP (NN matter)))))))) (VP (VBZ is) (VP (VBN called) (NP (NN potential)))) (. .)))