( ( THE ( PROBLEM ( The sun ) ) ) ( ( is ( ( the center ) ( of ( our ( solar system ) ) ) ) ) . ) )
(ROOT (S (NP (DT THE) (NNP PROBLEM) (NNP The) (NN sun)) (VP (VBZ is) (NP (NP (DT the) (NN center)) (PP (IN of) (NP (PRP$ our) (JJ solar) (NN system))))) (. .)))
THE PROBLEM The sun is the center of our solar system.
(ROOT (S (NP (DT The) (NN sun)) (VP (VBZ is) (VP (VBN considered) (NP (NP (DT the) (NN center)) (PP (IN of) (NP (DT the) (JJ solar) (NN system)))))) (. .)))