( ( At ( this temperature ) ) ( , ( ( nuclear energy ) ( ( is ( ( released ( by ( ( the fusion ) ( of hydrogen ) ) ) ) ( to ( form helium ) ) ) ) ; ) ) ) )
(ROOT (S (PP (IN At) (NP (DT this) (NN temperature))) (, ,) (NP (JJ nuclear) (NN energy)) (VP (VBZ is) (VP (VBN released) (PP (IN by) (NP (NP (DT the) (NN fusion)) (PP (IN of) (NP (NN hydrogen))))) (S (VP (TO to) (VP (VB form) (NP (NNP helium))))))) (: ;)))
At this temperature, nuclear energy is released by the fusion of hydrogen to form helium;
(ROOT (S (NP (NP (NNS Collisions)) (PP (IN between) (NP (NN hydrogen) (NNS atoms)))) (VP (VBP demonstrate) (NP (NP (CD one) (NN form)) (PP (IN of) (NP (JJ nuclear) (NN fusion))))) (. .)))