'You've double-crossed me about four times in one afternoon.
( ` ( You ( ( 've ( ( double-crossed me ) ( ( ( about four ) times ) ( in ( one afternoon ) ) ) ) ) . ) ) )
(ROOT (S (`` `) (NP (PRP You)) (VP (VBP 've) (VP (VBD double-crossed) (NP (PRP me)) (PP (NP (QP (RB about) (CD four)) (NNS times)) (IN in) (NP (CD one) (NN afternoon))))) (. .)))
I have to fire you because you won't stop crossing me. 
( I ( ( have ( to ( ( fire you ) ( because ( you ( ( wo n't ) ( stop ( crossing me ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP I)) (VP (VBP have) (S (VP (TO to) (VP (VB fire) (NP (PRP you)) (SBAR (IN because) (S (NP (PRP you)) (VP (MD wo) (RB n't) (VP (VB stop) (S (VP (VBG crossing) (NP (PRP me)))))))))))) (. .)))