In recent years, automatic question generation (QG), which aims to generate natural questions based on a certain type of data sources including structured knowledge bases (Serban et al., 2016b;Guo et al., 2018) and unstructured texts (Rus et al., 2010;Heilman and Smith, 2010;Du et al., 2017;Du and Cardie, 2018), has been widely studied.
previous works mainly focus on generating standalone and independent questions based on a given passage.