( ( A watershed ) ( ( is ( ( all ( the land ) ) ( drained ( by ( a ( ( stream or ) river ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (NN watershed)) (VP (VBZ is) (NP (NP (PDT all) (DT the) (NN land)) (VP (VBN drained) (PP (IN by) (NP (DT a) (NN stream) (CC or) (NN river)))))) (. .)))
A watershed is all the land drained by a stream or river.
(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)))))))