What have we for lunch? 
( What ( ( ( have we ) ( for lunch ) ) ? ) )
(ROOT (SBARQ (WHNP (WP What)) (SQ (VP (VBP have) (NP (PRP we)) (PP (IN for) (NP (NN lunch))))) (. ?)))
What did they serve for lunch?
( What ( ( ( did they ) ( serve ( for lunch ) ) ) ? ) )
(ROOT (SBARQ (WHNP (WP What)) (SQ (VBD did) (NP (PRP they)) (VP (VB serve) (PP (IN for) (NP (NN lunch))))) (. ?)))