I haven't prepared for it yet
Have I already prepared for it? (yes or no (general) question)
Why haven't I prepared for it yet? (why have I already prepared for it?) ( ,,WH,, (special) question)
who hasn't prepared for it yet?
Have I already prepared for it or not? ( ,,or,, (alternative question)
I haven't prepared for it yet, have I? (tag (disjunctive) question)
