( Mercury ( ( is ( ( a planet ) ( within ( the sun ) ) ) ) . ) )
(ROOT (S (NP (NNP Mercury)) (VP (VBZ is) (NP (NP (DT a) (NN planet)) (PP (IN within) (NP (DT the) (NN sun))))) (. .)))
Mercury is a planet within the sun.
(ROOT (S (NP (NNP Mercury)) (VP (VBZ is) (ADJP (ADJP (JJS closest)) (PP (TO to) (NP (PRP$ our) (NN sun))))) (. .)))