( ( ( Boiling Point ) ( The ( temperature ( ( at which ) ( ( a liquid ) ( becomes ( a gas ) ) ) ) ) ) ) . )
(ROOT (SINV (VP (VBG Boiling)) (VP (VBZ Point)) (NP (DT The) (NN temperature) (SBAR (WHPP (IN at) (WHNP (WDT which))) (S (NP (DT a) (NN liquid)) (VP (VBZ becomes) (NP (DT a) (NN gas)))))) (. .)))
Boiling Point The temperature at which a liquid becomes a gas.
(ROOT (S (NP (NNS Gases) (CC and) (NNS liquids)) (VP (VBP become) (NP (NNS solids)) (PP (IN at) (NP (JJ low) (NNS temperatures)))) (. .)))
Gases and liquids become solids at low temperatures.