( ( As ( the ( water evaporates ) ) ) ( , ( it ( ( will ( ( increase ( the humidity ) ) ( around ( the plants ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN As) (NP (DT the) (NN water) (NNS evaporates))) (, ,) (NP (PRP it)) (VP (MD will) (VP (VB increase) (NP (DT the) (NN humidity)) (PP (IN around) (NP (DT the) (NNS plants))))) (. .)))
As the water evaporates, it will increase the humidity around the plants.
(ROOT (S (NP (NNP Humidity) (NNP happens)) (VP (VBZ happens) (SBAR (WHADVP (WRB when)) (S (NP (JJ liquid) (NN water)) (VP (VBZ evaporates))))) (. .)))