( ( When ( it ( is hot ) ) ) ( ( a crocodile ) ( ( can ( ( cool off ) ( by ( holding ( ( its mouth ) open ) ) ) ) ) . ) ) )
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (PRP it)) (VP (VBZ is) (ADJP (JJ hot))))) (NP (DT a) (NN crocodile)) (VP (MD can) (VP (VB cool) (PRT (RP off)) (PP (IN by) (S (VP (VBG holding) (S (NP (PRP$ its) (NN mouth)) (ADJP (JJ open)))))))) (. .)))
When it is hot a crocodile can cool off by holding its mouth open.
(ROOT (S (S (VP (VBG Lying) (PP (IN with) (NP (PRP$ their) (NNS mouths))) (ADVP (RB open)))) (, ,) (NP (DT a) (NN behavior)) (VP (VBD called) (SBAR (S (NP (NNP gaping)) (, ,) (ADVP (RB probably)) (VP (VBZ serves) (NP (NP (DT the) (NN function)) (PP (IN of) (S (VP (VBG cooling) (PRT (RP down)) (PP (IN for) (NP (NNS crocodiles))))))))))) (. .)))