( ( ( ( It ( ( 's not ) ( ( ( an airplane ) or ) ( a UFO ) ) ) ) -- ) ( it ( 's ( ( Jupiter , ) ( ( the ( largest planet ) ) ( in ( the ( solar system ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (PRP It)) (VP (VBZ 's) (RB not) (NP (NP (DT an) (NN airplane)) (CC or) (NP (DT a) (NNP UFO))))) (: --) (S (NP (PRP it)) (VP (VBZ 's) (NP (NP (NNP Jupiter)) (, ,) (NP (NP (DT the) (JJS largest) (NN planet)) (PP (IN in) (NP (DT the) (JJ solar) (NN system))))))) (. .)))
It's not an airplane or a UFO -- it's Jupiter, the largest planet in the solar system.
(ROOT (S (NP (NNP Jupiter)) (VP (VBZ is) (NP (NP (DT the) (JJS largest) (NN planet)) (PP (IN in) (NP (PRP$ our) (JJ solar) (NN system))))) (. .)))