Previous approaches to machine comprehension are usually based on pairwise sequence matching, where either the passage is matched against the sequence that concatenates both the question and a candidate answer (Yin et al., 2016), or the passage is matched against the question alone followed by a second step of selecting an answer using the matching result of the first step (Lai et al., 2017;Zhou et al., 2018).
these approaches may not be suitable for multi-choice reading comprehension since questions and answers are often equally important.