( Pulsars ( ( are ( ( ( ` ( neutron ( stars ' ) ) ) , ) ( which ( form ( in ( ( the aftermath ) ( of ( a ( supernova explosion ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Pulsars)) (VP (VBP are) (NP (NP (`` `) (NN neutron) (NNS stars) ('' ')) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBP form) (PP (IN in) (NP (NP (DT the) (NN aftermath)) (PP (IN of) (NP (DT a) (NN supernova) (NN explosion)))))))))) (. .)))
Pulsars are 'neutron stars', which form in the aftermath of a supernova explosion.
(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))))) (. .)))