She's a crutch.
( She ( ( 's ( a crutch ) ) . ) )
(ROOT (S (NP (PRP She)) (VP (VBZ 's) (NP (DT a) (NN crutch))) (. .)))
She's an essential, key role in this, and is being used as a crutch.
( She ( ( ( ( ( 's ( ( an ( essential ( , ( key role ) ) ) ) ( in this ) ) ) , ) and ) ( is ( being ( used ( as ( a crutch ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP She)) (VP (VP (VBZ 's) (NP (NP (DT an) (JJ essential) (, ,) (JJ key) (NN role)) (PP (IN in) (NP (DT this))))) (, ,) (CC and) (VP (VBZ is) (VP (VBG being) (VP (VBN used) (PP (IN as) (NP (DT a) (NN crutch))))))) (. .)))