( ( More ( Saturn ( Background ( Three spacecraft ) ) ) ) ( ( have ( visited ( the ( sixth planet ) ) ) ) . ) )
(ROOT (S (NP (NNP More) (NNP Saturn) (NNP Background) (NNP Three) (NN spacecraft)) (VP (VBP have) (VP (VBN visited) (NP (DT the) (JJ sixth) (NN planet)))) (. .)))
More Saturn Background Three spacecraft  have visited the sixth planet.
(ROOT (S (NP (DT The) (NN voyager) (CD 1) (NN spacecraft)) (VP (VBD visited) (NP (NN saturn)) (PP (IN in) (NP (CD 1980)))) (. .)))