Although there exists a number of large-scale MRC datasets (Rajpurkar et al., 2016;Trischler et al., 2016;Bajaj et al., 2016;Zhang et al., 2018), collecting such highquality datasets is expensive and time-consuming, which hinders real-world applications for domainspecific MRC.
the ability to transfer an MRC model trained in a high-resource domain to other lowresource domains is critical for scalable MRC.