desu ka - lagu inget ka mantan

In main clauses (like your examples), da is deleted before ka: desu + ka → desu ka deshita + ka → deshita ka da + ka → ka datta + ka → datta ka. ka rapih dhoho In subordinate clauses (like [dare da ka] shiranai ), da sometimes appears before ka. ka turangga kecelakaan Although you want a short answer, you should also consider alternate ways of forming questions, for example