( ( The sun ) ( ( ( stays ( in ( its position ) ) ) ( at ( ( the center ) ( of ( our ( solar system ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN sun)) (VP (VBZ stays) (PP (IN in) (NP (PRP$ its) (NN position))) (PP (IN at) (NP (NP (DT the) (NN center)) (PP (IN of) (NP (PRP$ our) (JJ solar) (NN system)))))) (. .)))
The              sun stays in its position at the center of our solar system.
(ROOT (S (NP (DT The) (NN sun)) (VP (VBZ is) (NP (NP (DT the) (NN center)) (PP (IN of) (NP (PRP$ our) (JJ solar) (NN system))))) (. .)))
The sun is the center of our solar system.