( ( If ( ( ( ( the ( temperature changes ) ) and ) ( ( the number ) ( of ( gas molecules ) ) ) ) ( are ( kept constant ) ) ) ) ( , ( ( ( ( ( ( then ( either ( ( pressure or ) volume ) ) ) -LRB- ) or ) both ) -RRB- ) ( ( will ( ( change ( in ( direct proportion ) ) ) ( to ( the temperature ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN If) (S (NP (NP (DT the) (NN temperature) (NNS changes)) (CC and) (NP (NP (DT the) (NN number)) (PP (IN of) (NP (NN gas) (NNS molecules))))) (VP (VBP are) (VP (VBN kept) (S (ADJP (JJ constant))))))) (, ,) (NP (NP (RB then) (DT either) (NN pressure) (CC or) (NN volume)) (-LRB- -LRB-) (CC or) (NP (DT both)) (-RRB- -RRB-)) (VP (MD will) (VP (VB change) (PP (IN in) (NP (JJ direct) (NN proportion))) (PP (TO to) (NP (DT the) (NN temperature))))) (. .)))
If the temperature changes and the number of gas molecules are kept constant, then either pressure or volume (or both) will change in direct proportion to the 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)))))) (. .)))