Depending on the characteristics of the dataset, answers can be selected either from entities in the constructed entity graph (Song et al., 2018;Dhingra et al., 2018; De Cao et al., 2019; Tu et al., 2019; Ding et al., 2019), or from spans in documents by fusing entity representations back into token-level document representation (Xiao et al., 2019).
the constructed graph is mostly used for answer prediction only, while insufficient for finding supporting facts.