what was the problem
( what ( was ( the problem ) ) )
(ROOT (SBARQ (WHNP (WP what)) (SQ (VBD was) (NP (DT the) (NN problem)))))
Was the problem easy to fix?
( ( ( Was ( the problem ) ) ( easy ( to fix ) ) ) ? )
(ROOT (SQ (VBD Was) (NP (DT the) (NN problem)) (ADJP (JJ easy) (PP (TO to) (NP (NN fix)))) (. ?)))