( ( Elastic energy ) ( ( ( is sometimes ) ( ( called ( elastic ( potential energy ) ) ) ( because ( it ( can ( be ( recovered ( when ( ( the object ) ( returns ( to ( its ( original shape ) ) ) ) ) ) ) ) ) ) ) ) ) ; ) )
(ROOT (S (NP (JJ Elastic) (NN energy)) (VP (VBZ is) (ADVP (RB sometimes)) (VP (VBN called) (NP (JJ elastic) (JJ potential) (NN energy)) (SBAR (IN because) (S (NP (PRP it)) (VP (MD can) (VP (VB be) (VP (VBN recovered) (SBAR (WHADVP (WRB when)) (S (NP (DT the) (NN object)) (VP (VBZ returns) (PP (TO to) (NP (PRP$ its) (JJ original) (NN shape))))))))))))) (: ;)))
Elastic energy is sometimes called elastic potential energy because it can be recovered when the object returns to its original shape;
(ROOT (S (S (VP (VBG Changing) (NP (NP (DT the) (NN shape)) (PP (IN of) (NP (DT an) (JJ elastic) (NN material)))))) (VP (VBZ gives) (NP (PRP it)) (NP (JJ potential) (NN energy))) (. .)))