“…2015; Serban et al, 2016Serban et al, , 2017Zhang et al, 2018bZhang et al, , 2020 or retrieval-based manner (Lowe et al, 2015;Wu et al, 2017;Zhou et al, 2018;Tao et al, 2019a,b;Gu et al, 2019aGu et al, ,b, 2020. Recently, researchers have paid more attention to a more practical and challenging scenario involving more than two participants, which is well known as multiparty conversation (MPC) (Ouchi and Tsuboi, 2016;Zhang et al, 2018a;Le et al, 2019;. Table 1 shows an MPC example in the Ubuntu Internet Relay Chat (IRC) channel, which is composed of a sequence of (speaker, utterance, addressee) triples.…”