( ( The hydrosphere ) ( ( is ( ( ( ( ( the water ) -LRB- ) ( mainly ( the ( ( oceans and ) seas ) ) ) ) -RRB- ) ( on ( the ( Earth ( s surface ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN hydrosphere)) (VP (VBZ is) (NP (NP (NP (DT the) (NN water)) (-LRB- -LRB-) (NP (RB mainly) (DT the) (NNS oceans) (CC and) (NNS seas)) (-RRB- -RRB-)) (PP (IN on) (NP (DT the) (NNP Earth) (NNP s) (NN surface))))) (. .)))
The hydrosphere is the water (mainly the oceans and seas) on 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))))))))) (. .)))