( ( When ( ( the ( water vapor ) ) ( is ( cooled ( below ( the ( dew point ) ) ) ) ) ) ) ( , ( it ( ( condenses ( to ( form clouds ) ) ) . ) ) ) )
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (DT the) (NN water) (NN vapor)) (VP (VBZ is) (VP (VBN cooled) (PP (IN below) (NP (DT the) (NN dew) (NN point))))))) (, ,) (NP (PRP it)) (VP (VBZ condenses) (S (VP (TO to) (VP (VB form) (NP (NNS clouds)))))) (. .)))
When the water vapor is cooled below the dew point, it condenses to form clouds.
(ROOT (S (NP (NP (NNP Dew)) (VP (VBG forming) (PP (IN on) (NP (NNS plants))) (PP (IN during) (NP (DT a) (JJ cold) (NN night))))) (VP (VBZ is) (NP (NP (DT an) (NN example)) (PP (IN of) (NP (NN water) (NN condensing))))) (. .)))