( ( If ( ( ( Virginia 's ) ( power plants ) ) ( were ( cleaned up ) ) ) ) ( , ( ( ( the ( resulting improvement ) ) ( in ( air quality ) ) ) ( ( would ( be ( equivalent ( to ( ( taking ( ( 4 million ) cars ) ) ( off ( the road ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN If) (S (NP (NP (NNP Virginia) (POS 's)) (NN power) (NNS plants)) (VP (VBD were) (VP (VBN cleaned) (PRT (RP up)))))) (, ,) (NP (NP (DT the) (VBG resulting) (NN improvement)) (PP (IN in) (NP (NN air) (NN quality)))) (VP (MD would) (VP (VB be) (ADJP (JJ equivalent) (PP (TO to) (S (VP (VBG taking) (NP (QP (CD 4) (CD million)) (NNS cars)) (PP (IN off) (NP (DT the) (NN road))))))))) (. .)))
If Virginia's power plants were cleaned up, the resulting improvement in air quality would be equivalent to taking 4 million cars off the road.
(ROOT (S (S (VP (VBG Limiting) (NP (NP (DT the) (NN number)) (PP (IN of) (NP (NP (NNS cars)) (PP (IN on) (NP (DT the) (NNS roads)))))))) (VP (MD would) (ADVP (RBS most) (RB likely)) (VP (VB improve) (NP (DT the) (NN air) (NN quality)) (PP (IN in) (NP (JJ large) (NNS texas) (NNS cities))))) (. .)))