( ( While ( ( ( the center ) ( of ( ( the ( earth 's ) ) core ) ) ) ( is solid ) ) ) ( , ( ( the ( outer ( 1,500 miles ) ) ) ( ( are ( made ( of ( ( ( ( liquid metals ) , ) mostly ) iron ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN While) (S (NP (NP (DT the) (NN center)) (PP (IN of) (NP (NP (DT the) (NN earth) (POS 's)) (NN core)))) (VP (VBZ is) (ADJP (JJ solid))))) (, ,) (NP (DT the) (JJ outer) (CD 1,500) (NNS miles)) (VP (VBP are) (VP (VBN made) (PP (IN of) (NP (NP (JJ liquid) (NNS metals)) (, ,) (RB mostly) (NP (NN iron)))))) (. .)))
While the center of the earth's core is solid, the outer 1,500 miles are made of liquid metals, mostly iron.
(ROOT (S (NP (DT The) (JJ outer) (NN core)) (VP (VBZ is) (VP (VBN made) (PP (IN of) (NP (JJ liquid) (NN metal))))) (. .)))