Then we can sample multiple triples of this dialogue as utterance pair triples using the following strategies: • Ordered triple sampling: We sample a triple following the dialogue sequential order as • Misordered triple sampling: The three utterance pairs are sampled in a triple as Note that when the current dialogue length t <= 2, it is not enough to get a rational sampling for utterance pair triples.
we add three extra shared padding utterance pairs (Q −2 , A −2 ), (Q −1 , A −1 ) and (Q 0 , A 0 ) ahead of all the dialogue data before sampling 1 .