( ( For example ) ( , ( ( ( ( ( hydraulic fracturing ) , ) ( aka fracking ) ) , ) ( ( has ( ( ( opened up ) ( numerous ( oil fields ) ) ) ( in ( areas ( that ( were ( once ( considered ( ( ( played out ) or ) ( too ( costly ( to develop ) ) ) ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN For) (NP (NN example))) (, ,) (NP (NP (JJ hydraulic) (NN fracturing)) (, ,) (NP (NN aka) (NN fracking)) (, ,)) (VP (VBZ has) (VP (VBN opened) (PRT (RP up)) (NP (JJ numerous) (NN oil) (NNS fields)) (PP (IN in) (NP (NP (NNS areas)) (SBAR (WHNP (WDT that)) (S (VP (VBD were) (VP (ADVP (RB once)) (VBN considered) (UCP (VP (VBN played) (PRT (RP out))) (CC or) (ADJP (RB too) (JJ costly) (S (VP (TO to) (VP (VB develop)))))))))))))) (. .)))
For example, hydraulic fracturing, aka fracking , has opened up numerous oil fields in areas that were once considered played out or too costly to develop.
(ROOT (S (NP (NNP Fracking)) (VP (VBZ is) (NP (NP (DT another) (NN term)) (PP (IN for) (NP (JJ hydraulic) (NN fracturing))))) (. .)))