( ( Le Verrier ) ( , ( however ( , ( ( ( attributed this ) ( to ( ( ( a planet ) , ) ( which ( he ( ( called ( ( Vulcan , ) ( closer ( ( ( to ( ( the Sun ) ( than Mercury ) ) ) or ) ( to ( a ( second ( asteroid belt ) ) ) ) ) ) ) ) ( ( so ( close ( to ( the Sun ) ) ) ) ( as ( to ( be invisible ) ) ) ) ) ) ) ) ) ) . ) ) ) ) )
(ROOT (S (NP (NNP Le) (NNP Verrier)) (, ,) (ADVP (RB however)) (, ,) (VP (VBD attributed) (NP (DT this)) (PP (TO to) (NP (NP (DT a) (NN planet)) (, ,) (SBAR (WHNP (WDT which)) (S (NP (PRP he)) (VP (VBD called) (NP (NP (NNP Vulcan)) (, ,) (NP (NP (JJR closer)) (PP (PP (TO to) (NP (NP (DT the) (NNP Sun)) (PP (IN than) (NP (NNP Mercury))))) (CC or) (PP (TO to) (NP (DT a) (JJ second) (JJ asteroid) (NN belt)))))) (ADVP (ADVP (RB so) (JJ close) (PP (TO to) (NP (DT the) (NNP Sun)))) (SBAR (IN as) (S (VP (TO to) (VP (VB be) (ADJP (JJ invisible))))))))))))) (. .)))
Le Verrier, however, attributed this to a planet, which he called Vulcan, closer to the Sun than Mercury or to a second asteroid belt so close to the Sun as to be invisible.
(ROOT (S (NP (NNP Mercury)) (VP (VBZ is) (ADJP (ADJP (JJS closest)) (PP (TO to) (NP (DT the) (NN sun))))) (. .)))