“…(2) Information extraction-based approaches ( [33], [34], [35], [36]), which firstly extract important information units, such as Subject-Verb-Object triples, from documents and then generate new descriptions for them based on manually designed templates or patterns learned from corpus. (3) Paraphrasing based approaches ( [37], [38], [39], [40]), which paraphrase the original sentences with sentence rewriting rules, such as sentence compression, phrases substitution and co-reference resolution, to generate more informative and concise summaries.…”