( And ( ( during ( ( the ( first half ) ) ( of ( this century ) ) ) ) ( ( many astronomers ) ( ( thought ( that ( Venus ( was ( ( the planet ) ( most ( likely ( to ( ( have ( ( life forms ) other ) ) ( than ( our ( planet Earth ) ) ) ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (CC And) (PP (IN during) (NP (NP (DT the) (JJ first) (NN half)) (PP (IN of) (NP (DT this) (NN century))))) (NP (JJ many) (NNS astronomers)) (VP (VBD thought) (SBAR (IN that) (S (NP (NNP Venus)) (VP (VBD was) (NP (NP (DT the) (NN planet)) (ADJP (RBS most) (JJ likely) (S (VP (TO to) (VP (VB have) (S (NP (NN life) (NNS forms)) (ADJP (JJ other))) (PP (IN than) (NP (PRP$ our) (NN planet) (NN Earth)))))))))))) (. .)))
And during the first half of this century many astronomers thought that Venus was the planet most likely to have life forms other than our planet Earth.
(ROOT (S (NP (NNP Venus)) (VP (VBZ has) (NP (DT the) (JJS most) (NNS volcanoes))) (. .)))