( ( ( ( ( We ( ( do n't ) ( know ( for sure ) ) ) ) , ) but ) ( it ( ( is possible ) ( that ( Venus ( ( has ( more volcanoes ) ) ( than ( any ( of ( ( the ( other planets ) ) ( in ( our ( Solar System ) ) ) ) ) ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (PRP We)) (VP (VBP do) (RB n't) (VP (VB know) (PP (IN for) (ADJP (JJ sure)))))) (, ,) (CC but) (S (NP (PRP it)) (VP (VBZ is) (ADJP (JJ possible)) (SBAR (IN that) (S (NP (NNP Venus)) (VP (VBZ has) (NP (JJR more) (NNS volcanoes)) (PP (IN than) (NP (NP (DT any)) (PP (IN of) (NP (NP (DT the) (JJ other) (NNS planets)) (PP (IN in) (NP (PRP$ our) (NNP Solar) (NNP System)))))))))))) (. .)))
We don't know for sure, but it is possible that Venus has more volcanoes than any of the other planets in our Solar System.
(ROOT (S (NP (NNP Venus)) (VP (VBZ has) (NP (DT the) (JJS most) (NNS volcanoes))) (. .)))