( ( The ( latent heat ) ) ( ( is ( ( ( the heat ) ( ( absorbed or ) ( released ( -LRB- ( ( at ( constant temperature ) ) -RRB- ) ) ) ) ) ( to ( change ( ( the phase ) ( of ( a substance ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN latent) (NN heat)) (VP (VBZ is) (NP (NP (DT the) (NN heat)) (VP (VP (VBN absorbed)) (CC or) (VP (VBN released) (PRN (-LRB- -LRB-) (PP (IN at) (NP (JJ constant) (NN temperature))) (-RRB- -RRB-)))) (S (VP (TO to) (VP (VB change) (NP (NP (DT the) (NN phase)) (PP (IN of) (NP (DT a) (NN substance))))))))) (. .)))
The latent heat is the heat absorbed or released (at constant temperature) to change the phase of a substance.
(ROOT (S (PP (IN During) (NP (NN phase) (NN change))) (, ,) (NP (NP (DT the) (NN temperature)) (PP (IN of) (NP (DT a) (NN system)))) (VP (VBZ remains) (ADJP (JJ constant))) (. .)))