( nuclear ( ( fusion ( ( A ( nuclear process ) ) ( that ( releases ( energy ( when ( ( lightweight nuclei ) ( combine ( to ( form ( heavy-weight nuclei ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (JJ nuclear)) (VP (VBZ fusion) (NP (NP (DT A) (JJ nuclear) (NN process)) (SBAR (WHNP (WDT that)) (S (VP (VBZ releases) (NP (NP (NN energy)) (SBAR (WHADVP (WRB when)) (S (NP (JJ lightweight) (NNS nuclei)) (VP (VBP combine) (S (VP (TO to) (VP (VB form) (NP (JJ heavy-weight) (NNS nuclei)))))))))))))) (. .)))
nuclear fusion A nuclear process that releases energy when lightweight nuclei combine to form heavy-weight nuclei.
(ROOT (S (PP (IN In) (NP (DT the) (JJ nuclear) (NN fusion) (NN process))) (, ,) (NP (CD two) (JJ light) (NNS nuclei)) (VP (VBP combine) (S (VP (TO to) (VP (VB produce) (NP (NP (DT a) (JJR heavier) (NN nucleus)) (CC and) (NP (JJ great) (NN energy))))))) (. .)))