( ( The ( remaining ( neutron core ) ) ) ( ( left ( after ( ( a ( supernova explosion ) ) ( forms ( the ( neutron star ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (VBG remaining) (NN neutron) (NN core)) (VP (VBD left) (SBAR (IN after) (S (NP (DT a) (NN supernova) (NN explosion)) (VP (VBZ forms) (NP (DT the) (NN neutron) (NN star)))))) (. .)))
The remaining neutron core left after a supernova explosion forms the neutron star.
(ROOT (S (NP (NN Neutron) (NNS stars)) (VP (VBP are) (NP (NP (DT the) (NNS corpses)) (PP (IN of) (NP (ADJP (VBN left) (RP over)) (NN supernova) (NNS explosions))))) (. .)))