i can believe i can believe that
( i ( can ( believe ( i ( can ( believe that ) ) ) ) ) )
(ROOT (S (NP (FW i)) (VP (MD can) (VP (VB believe) (SBAR (S (NP (FW i)) (VP (MD can) (VP (VB believe) (NP (DT that))))))))))
I don't believe that for a second.
( I ( ( ( do n't ) ( believe ( that ( for ( a second ) ) ) ) ) . ) )
(ROOT (S (NP (PRP I)) (VP (VBP do) (RB n't) (VP (VB believe) (NP (NP (DT that)) (PP (IN for) (NP (DT a) (NN second)))))) (. .)))