11 Let (q i , [a i0 , ..., a im ]) be a question with its possible answers, we first create a set of m queries of the form [q i + a i0 , ..., q i + a im ], which will be sent separately to a search engine.
we use the DrQA's Document Retriever (Chen et al., 2017), which scores the relation between the queries and the articles as TF-IDF weighted bagof-word vectors, and also takes into account word order and bi-gram counting.