, so who knew charles dickens could be so light-hearted ? 
(ROOT (S (, ,) (RB so) (WHNP (WP who)) (SQ (VP (VBD knew) (SBAR (S (NP (NNP charles) (NNP dickens)) (VP (MD could) (VP (VB be) (ADJP (RB so) (JJ light) (HYPH -) (JJ hearted)))))))) (. ?)))
(ROOT (S (, ) (RB ) (WHNP (WP )) (SQ (VP (VBD ) (SBAR (S (NP (NNP ) (NNP )) (VP (MD ) (VP (VB ) (ADJP (RB ) (JJ ) (HYPH ) (JJ )))))))) (. )))