( HYDROSPHERE ( ( Considered ( as ( ( the ( water portion ) ) ( of ( ( the ( earth 's ) ) surface ) ) ) ) ) . ) )
(ROOT (S (NP (NNP HYDROSPHERE)) (VP (VBN Considered) (PP (IN as) (NP (NP (DT the) (NN water) (NN portion)) (PP (IN of) (NP (NP (DT the) (NN earth) (POS 's)) (NN surface)))))) (. .)))
HYDROSPHERE Considered as the water portion of the earth's surface.
(ROOT (S (NP (NP (DT The) (NN surface)) (PP (IN of) (NP (NN earth)))) (VP (VBZ is) (VP (VBN covered) (PP (IN by) (NP (NP (DT a) (ADJP (RB relatively) (JJ thin)) (NN layer)) (PP (IN of) (NP (NP (NN water)) (VP (VBN called) (NP (DT the) (NN hydrosphere))))))))) (. .)))