When was that?
( When ( ( was that ) ? ) )
(ROOT (SBARQ (WHADVP (WRB When)) (SQ (VBD was) (NP (DT that))) (. ?)))
When was your graduation?
( When ( ( was ( your graduation ) ) ? ) )
(ROOT (SBARQ (WHADVP (WRB When)) (SQ (VBD was) (NP (PRP$ your) (NN graduation))) (. ?)))