task_categories:question-answering task_categories:summarization task_categories:text-generation task_ids:multiple-choice-qa language:en arxiv:2104.02112 arxiv:2104.07091 arxiv:2104.05938 arxiv:2205.11465 arxiv:2105.03011 arxiv:1712.07040 arxiv:2112.08608 arxiv:2108.00573 region:us query-based-summarization long-texts