( ( When ( ( ( ( the temperature ) ( is high ) ) and ) ( ( the ( relative humidity ) ) ( is low ) ) ) ) ( , ( ( evaporation ( of water ) ) ( ( is rapid ) ; ) ) ) )
(ROOT (S (SBAR (WHADVP (WRB When)) (S (S (NP (DT the) (NN temperature)) (VP (VBZ is) (ADJP (JJ high)))) (CC and) (S (NP (DT the) (JJ relative) (NN humidity)) (VP (VBZ is) (ADJP (JJ low)))))) (, ,) (NP (NP (NN evaporation)) (PP (IN of) (NP (NN water)))) (VP (VBZ is) (ADJP (JJ rapid))) (: ;)))
When the temperature is high and the relative humidity is low, evaporation of water is rapid;
(ROOT (S (NP (NNP Humidity) (NNP happens)) (VP (VBZ happens) (SBAR (WHADVP (WRB when)) (S (NP (JJ liquid) (NN water)) (VP (VBZ evaporates))))) (. .)))