( ( ( The burning ) ( of ( ( ( fossil fuels ) ( -LRB- ( ( ( coal and ) oil ) -RRB- ) ) ) ( by ( power-production ( ( companies and ) industries ) ) ) ) ) ) ( ( ( releases sulfur ) ( into ( ( ( the air ) ( that ( ( combines ( with oxygen ) ) ( to ( form ( sulfur dioxide ) ) ) ) ) ) ( -LRB- ( ( SO 2 ) -RRB- ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN burning)) (PP (IN of) (NP (NP (NP (JJ fossil) (NNS fuels)) (PRN (-LRB- -LRB-) (NP (NP (NN coal)) (CC and) (NP (NN oil))) (-RRB- -RRB-))) (PP (IN by) (NP (JJ power-production) (NNS companies) (CC and) (NNS industries)))))) (VP (VBZ releases) (NP (NN sulfur)) (PP (IN into) (NP (NP (DT the) (NN air)) (SBAR (WHNP (WDT that)) (S (VP (VBZ combines) (PP (IN with) (NP (NN oxygen))) (S (VP (TO to) (VP (VB form) (NP (NN sulfur) (NN dioxide)))))))) (PRN (-LRB- -LRB-) (NP (NNP SO) (CD 2)) (-RRB- -RRB-))))) (. .)))
The burning of fossil fuels (coal and oil) by power-production companies and industries releases sulfur into the air that combines with oxygen to form sulfur dioxide (SO 2 ).
(ROOT (S (NP (DT The) (NN element) (NN sulfur)) (VP (VBZ is) (VP (VBN released) (PP (IN into) (NP (DT the) (NN atmosphere))) (PP (IN by) (NP (NP (DT the) (NN burning)) (PP (IN of) (NP (JJ fossil) (NNS fuels))))))) (. .)))