“…Question Generation (QG) has a wide range of applications, such as generating questions for exams (Jia et al, 2021;Lelkes et al, 2021;Dugan et al, 2022) or children's story books (Zhao et al, 2022;Yao et al, 2022), recommending questions for users in a dialogue system (Shukla et al, 2019;Laban et al, 2020), improving visual (Li et al, 2018;Lu et al, 2022) or textual question-answering tasks (Duan et al, 2017;Lewis et al, 2019a;Zhang and Bansal, 2019;Sultan et al, 2020;Lyu et al, 2021), asking clarification questions (Rao and DaumĆ© III, 2019;Ren et al, 2021), and generating queries for SQL or multimodal documents (Kim et al, 2021). * Equal Contribution Previous works on QG are mainly under the openbook setting, which aims to generate questions based on factoid or human-generated short answers under the assumption that there is access to external knowledge like retrieved documents or passages (Du et al, 2017;Zhao et al, 2018;Kim et al, 2019;Fei et al, 2021).…”