( ( Condensation-Water vapor ) ( ( ( rises and ) ( condenses ( to ( form clouds ) ) ) ) . ) )
(ROOT (S (NP (NN Condensation-Water) (NN vapor)) (VP (VP (VBZ rises)) (CC and) (VP (VBZ condenses) (S (VP (TO to) (VP (VB form) (NP (NNS clouds))))))) (. .)))
Condensation-Water vapor rises and condenses to form clouds.
(ROOT (S (NP (NNP Condensation)) (VP (MD must) (VP (VB occur) (PP (IN for) (NP (NNS clouds))) (S (VP (TO to) (VP (VB form)))))) (. .)))