( ( ( The area ) ( of ( land ( drained ( by ( a river ) ) ) ) ) ) ( ( is ( called ( ( the river ) ( s watershed ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN area)) (PP (IN of) (NP (NP (NN land)) (VP (VBN drained) (PP (IN by) (NP (DT a) (NN river))))))) (VP (VBZ is) (VP (VBN called) (SBAR (S (NP (DT the) (NN river)) (VP (VBZ s) (NP (NN watershed))))))) (. .)))
The area of land drained by a river is called the river s watershed .
(ROOT (S (NP (NP (DT All)) (PP (IN of) (NP (NP (DT the) (NN land)) (VP (VBN drained) (PP (IN by) (NP (DT a) (NN river) (NN system))))))) (VP (VBZ is) (VP (VBN called) (NP (NP (PRP$ its) (NN basin)) (, ,) (CC or) (NP (DT the) (`` ``) (JJ wet) ('' '') (NN term) (NN watershed)))))))