Um, I'm sure I have I just can't think of what.
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(ROOT (S (ADVP (RB Um)) (, ,) (NP (PRP I)) (VP (VBP 'm) (ADJP (JJ sure) (SBAR (S (NP (PRP I)) (VP (VBP have) (S (NP (PRP I)) (ADVP (RB just)) (VP (MD ca) (RB n't) (VP (VB think) (PP (IN of) (NP (WP what))))))))))) (. .)))
I am pretty sure but I just can not think of what at the moment.
( ( ( ( I ( am ( pretty sure ) ) ) but ) ( I ( just ( ( can not ) ( ( think ( of what ) ) ( at ( the moment ) ) ) ) ) ) ) . )
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