As for Macbeth's great bond , this is a crux over which commentators have argued for years.
( ( As ( for ( ( Macbeth 's ) ( great bond ) ) ) ) ( , ( this ( ( is ( ( a crux ) ( over ( which ( commentators ( have ( argued ( for years ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN As) (PP (IN for) (NP (NP (NNP Macbeth) (POS 's)) (JJ great) (NN bond)))) (, ,) (NP (DT this)) (VP (VBZ is) (NP (NP (DT a) (NN crux)) (PP (IN over) (SBAR (WHNP (WDT which)) (S (NP (NNS commentators)) (VP (VBP have) (VP (VBN argued) (PP (IN for) (NP (NNS years)))))))))) (. .)))
People have argued over parts of the play for a long time.
( People ( ( have ( argued ( over ( parts ( of ( ( the play ) ( for ( a ( long time ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS People)) (VP (VBP have) (VP (VBN argued) (PP (IN over) (NP (NP (NNS parts)) (PP (IN of) (NP (NP (DT the) (NN play)) (PP (IN for) (NP (DT a) (JJ long) (NN time))))))))) (. .)))