a strategy for polarity question constructions in which both the positive and negative form of the proposition are expressed. Example: Mandarin tā zài jiā bu zài jiā [lit. 'S/he at home not at home'] 'Is s/he at home?' is an instance of the A–not-A strategy for polarity questions. The A–not-A strategy is essentially the recruitment of the alternative question construction for the polarity question function.