The first part starts with opening word, which introduces the background of the full text, and made a brief commentary to the entire article;

正文共有五章，第一章是绪论部分，对要论述问题的背景做出阐述并由此引出全文；

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Applications of organic, inorganic and natural high_molecular flocculants in printing and dyeing in recent years are introduced with brief commentary.

本文介绍了近年来无机、有机合成和天然高分子絮凝剂在印染废水处理中的应用，并进行了简要评述。

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This paper gives a brief commentary on the English proverb by discussing its sources, its linguistic features and its philosophic and instructive nature.

本文从英语谚语语法的来源、其语言特点及思想内容几方面对英语谚语进行了简要的评介。

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Seems Todd Wasserman of Mashable wrote a brief piece on the commercial and included some commentary and if you went strictly by what DraftFBC Buenos Aires shared via a Tweet, you would think Todd thought the spot was the be all, end all when it comes to advertising.

FORBES: New Ad Campaign Involves Killing Grandmom, Over & Over Again