what was the problem
( what ( was ( the problem ) ) )
(ROOT (SBARQ (WHNP (WP what)) (SQ (VBD was) (NP (DT the) (NN problem)))))
i know exactly what the problem is.
( i ( ( know ( ( exactly what ) ( ( the problem ) is ) ) ) . ) )
(ROOT (S (NP (FW i)) (VP (VBP know) (SBAR (WHADJP (RB exactly) (WP what)) (S (NP (DT the) (NN problem)) (VP (VBZ is))))) (. .)))