Neural question generation (NQG) has been extensively studied because of its broad application in question answering (QA) systems (Tang et al., 2018;Duan et al., 2017), reading comprehension (Kim et al., 2019;, and visual question answering (Fan et al., 2018).
the research of open-domain conversational question generation (CQG) Hu et al., 2018) is still in its infancy.