<cite>Jia and Liang (2017)</cite> presented some initial attempts to fix this problem by retraining the BiDAF model (Seo et al., 2017) with adversaries generated with <cite>AddSent</cite>. But <cite>they</cite> showed that the method is not very effective, as slight modifications (e.g., different positioning of the distractor sentence in the paragraph and different fake answer set) to the adversary generation algorithm at test time have drastic impact on the retrained model's performance.