( ( For example ) ( , ( ( ( the pressure ) ( of ( ( a gas ) ( in ( a ( fixed volume ) ) ) ) ) ) ( ( is ( directly ( proportional ( to ( its temperature ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN For) (NP (NN example))) (, ,) (NP (NP (DT the) (NN pressure)) (PP (IN of) (NP (NP (DT a) (NN gas)) (PP (IN in) (NP (DT a) (JJ fixed) (NN volume)))))) (VP (VBZ is) (ADJP (RB directly) (JJ proportional) (PP (TO to) (NP (PRP$ its) (NN temperature))))) (. .)))
For example, the pressure of a gas in a fixed volume is directly proportional to its temperature.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NN volume)) (VP (VBZ does) (RB not) (VP (VB change))))) (, ,) (NP (NN temperature)) (VP (VBZ is) (ADJP (JJ proportional) (S (VP (TO to) (VP (VB pressure)))))) (. .)))