( But ( Ceres ( ( was ( only ( ( ( considered ( ( a planet ) ( for ( a year ) ) ) ) , ) ( while ( Pluto ( has ( been ( ( a ( major planet ) ) ( for ( ( more ( than 70 ) ) years ) ) ) ) ) ) ) ) ) ) . ) ) )
(ROOT (S (CC But) (NP (NNP Ceres)) (VP (VBD was) (VP (ADVP (RB only)) (VBN considered) (NP (NP (DT a) (NN planet)) (PP (IN for) (NP (DT a) (NN year)))) (, ,) (SBAR (IN while) (S (NP (NNP Pluto)) (VP (VBZ has) (VP (VBN been) (NP (NP (DT a) (JJ major) (NN planet)) (PP (IN for) (NP (QP (JJR more) (IN than) (CD 70)) (NNS years)))))))))) (. .)))
But Ceres was only considered a planet for a year, while Pluto has been a major planet for more than 70 years.
(ROOT (S (NP (PRP We)) (VP (VBP consider) (S (NP (NNS ceres)) (VP (TO to) (VP (VB be) (NP (DT a) (NN dwarf) (NN planet)))))) (. .)))