( ( Gas ( plant operators ) ) ( also ( ( ( monitor machines ) ( as ( ( ( ( gases , ) ( such ( as ( ( oxygen and ) nitrogen ) ) ) ) , ) ( are created ) ) ) ) . ) ) )
(ROOT (S (NP (NNP Gas) (NN plant) (NNS operators)) (ADVP (RB also)) (VP (VBP monitor) (NP (NNS machines)) (SBAR (IN as) (S (NP (NP (NNS gases)) (, ,) (PP (JJ such) (IN as) (NP (NN oxygen) (CC and) (NN nitrogen))) (, ,)) (VP (VBP are) (VP (VBN created)))))) (. .)))
Gas plant operators also monitor machines as gases, such as oxygen and nitrogen, are created.
(ROOT (S (NP (NN Oxygen) (NN gas)) (VP (VBZ is) (VP (VBN given) (PRT (RP off)) (PP (IN by) (NP (NNS plants))))) (. .)))