Pattern
(+) Subject
+ Had + Verb3 +
Complement.
(–) Subject
+ Had + Not + Verb3 +
Complement.
(?) Had
+ Subject + Verb3 +
Complement?
(WH) WH + Had + Subject + Verb3 + Complement?
*When/Before – Simple Past, – Past Perfect.
*Past Perfect – When/Before – Simple Past.