Answer Chunking To reduce the errors generated by the rule-based chunker in<cite> (Rajpurkar et al. 2016)</cite> , first, we capture the part-of-speech (POS) pattern of all answer subsequences in the training dataset to form a POS pattern trie tree, and then apply the answer POS patterns to passage P i to acquire a collection of all subsequences (chunk candidates) C i whose POS patterns can be matched to the POS pattern trie.