( ( ( Mercury - ) ( ( the ( closest planet ) ) ( to ( the sun ) ) ) ) . )
(ROOT (NP (NP (NNP Mercury)) (: -) (NP (NP (DT the) (JJS closest) (NN planet)) (PP (TO to) (NP (DT the) (NN sun)))) (. .)))
Mercury -the closest planet to the sun .
(ROOT (S (NP (NNP Mercury)) (VP (VBZ is) (ADJP (ADJP (JJS closest)) (PP (TO to) (NP (DT the) (NN sun))))) (. .)))