Six words to ask anything: where, who, what, when, how much, how.
French question words mostly come at the start of the question, but can also slot at the end in casual speech. Où is "where", qui is "who", quoi is "what" (after a verb or preposition), quand is "when", combien is "how much/many", comment is "how". Some look similar — quand, quoi, qui — so listen for the vowel sound, that's where the meaning is.
Which question word fills the blank?