( We ( ( ( breathe ( the oxygen ) ) ( that ( plants ( give off ) ) ) ) ; ) )
(ROOT (S (NP (PRP We)) (VP (VBD breathe) (NP (DT the) (NN oxygen)) (SBAR (IN that) (S (NP (NNS plants)) (VP (VBP give) (PRT (RP off)))))) (: ;)))
We breathe the oxygen that plants give off;
(ROOT (S (NP (NN Oxygen) (NN gas)) (VP (VBZ is) (VP (VBN given) (PRT (RP off)) (PP (IN by) (NP (NNS plants))))) (. .)))