As for Macbeth's great bond , this is a crux over which commentators have argued for years.
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(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)))))))))) (. .)))
The bond has had many scholarly papers written about it,
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(ROOT (S (NP (DT The) (NN bond)) (VP (VBZ has) (VP (VBN had) (NP (NP (JJ many) (JJ scholarly) (NNS papers)) (VP (VBN written) (PP (IN about) (NP (PRP it))))))) (, ,)))