如果你的论文看上去晦涩难懂，那么重新组织你的论文结构、设计段落则是一个好方法。如果你不知道怎么表达清楚你的观点或者介绍清楚你的研究，那么可以通过设计论文各段落的主题帮助你规整思路。
这一期，笔者来和大家讨论一下SCI论文的段落Paragraphs——如何设计好论文的段落，提高论文的可读性，传达自己的观点。
本文主要包括5部分：段落的定义、段落的主题、段落的分类、段落的流畅性和段落的长度。看到这里有没有发现，原来论文段落有这么多讲究？
接下来我们进入主题！
一个段落可以是一个句子或一组句子，段落具有统一的主题。我们需要从主题统一的角度来思考和理解段落。段落体现主题的最有效方法就是用一个主题句来表达段落的中心思想。SCI论文有自己的主题，段落也有自己的主题。如果所有段落的主题都与论文的主题相关，那么文章就具有统一的主题。注意：并非所有段落都需要主题句。特别是开头和结尾段落一般没有主题句。在SCI论文写作中，一个段落的主题句通常最适合放在一个段落的开头，这样读者很容易理解这个段落的内容，例如: The embrace of Twitter by politicians and journalists has been one of its most notable features in recent years: for both groups the use of Twitter is becoming close to a requirement. 这个主题句介绍了该段的中心思想或要点:“政客”和“记者”依赖于Twitter。本段的其余部分将集中于这两个Twitter群体的描写。此外，通过避免与主题句无关的信息，从而实现段落主题的统一。
段落有很多种类，笔者主要给大家介绍5种常用段落类型：
定义段落
(definition paragraph)；
分析或分类段落
(analysis or classification paragraph)；
对比段落
(comparison or a contrast paragraph)；
鉴定段落
(qualification paragraph)；
过程段落
(process paragraph)
（1）定义段落主要用于定义一个术语，通常是通过区分术语和其他相关术语。定义通常是特定的领域，尽量避免字典上敷衍的定义，例如下面这个段落介绍了typology的定义。Our typology is built on three dimensions: internality, types of participants, and the degree of effective resistance. For our study, a civil war is any armed conflict that involves (a) military action internal to the metropole, (b) the active participation of the national government, and (c) effective resistance by both sides. With these criteria, we differentiate civil wars from other types of internal violent conflicts.（2）分析或分类段落主要是用于介绍一个主题的组成部分并分别展开讨论每个部分，例如像下面这个段落。Policies of privatisation should be considered as responses to several distinct pressures. First, privatisation is a response by the state to internal forces such as increasing fiscal problems (O’Connor, 1973). It provides a means of lessening the state’s fiscal responsibilities by encouraging the development of private alternatives which, theoretically at least, do not draw upon the state’s financial reserves. Second, the promotion of private sector activity is a response to pressures originating ‘outside’ the state apparatus. These include demands from people who see a large state bureaucracy as inefficient and wasteful, demands from business interests who claim that they can overcome these inefficiencies, and pressures from client groups who seek to reduce their dependency on the welfare state by having more control over the services on which they depend. Clearly, this variety of calls for privatisation means that it is not a process with a uniform outcome; there exists a correspondingly wide variety of forms of privatisation.（3）对比段落主要是用于分析一个主题的相似或不同之处，例如两个来源、位置或观点。段落可以是介绍相似点或者不同点，也可以同时介绍相似点和不同点。此外，你也可以在两个单独的段落中分别比较相同点或者不同点。最后强调一下，正如下面的段落主题句所表明的一样，你应该从一开始就让读者明白这个段落是对比段落。Evidence from industrialized countries suggests that compared with older men, older women more often experience functional impairments and activity limitations, have longer durations of disability, and spend proportionately more remaining years of life disabled.（4）鉴定段落主要是用于陈述之前的观点，例如下面这个段落。This study was a preliminary study of high school student value changes because of the terrorist attack on the U.S. The major limitations of this study were that the student population was from California and might not truly represent all high school students in the U.S. Further, this study could not be considered a truly longitudinal study because of privacy issues that prevented the researchers from identifying all the students who returned surveys before the attack. In addition, the senior class had graduated the previous year, and a much larger freshman class entered the school. These issues not only made the samples similar, but also different in their composition. The researchers will conduct periodic studies to explore whether these value changes are permanent and continue into adulthood. We do not know what if any changes will take place in their values as they grow older, and we will continue to explore their values in our longitudinal studies of the impact of the 9/11 terrorist attacks.（5）过程段落主要用于展示一个过程描述，通常遵循时间顺序。例如下面这个段落，首先总体介绍了干尸制作的工序，然后分别按步骤介绍具体过程，其中粗体字是重要的顺序词。In brief, the mummification process may be summarized as follows: extract, sterilize, dehydrate, perfume, seal, tag, and stock. All were done ceremoniously and with due respect to the dead body. The viscera were extracted through an incision about 10 inches long, usually made in the left side of the abdomen. Through this incision, all the “floating” contents of the abdominal cavity, namely, the stomach, the liver, the spleen, and the intestines, were removed but the kidneys were left in place. The diaphragm was then cut and the thoracic contents removed through the abdominal incision. The heart, which was considered the center of emotions and the seat of conscience, was left in place. The ancient Egyptians seem to have attached no importance to the brain, which was removed through the ethmoid bone. Following these extractions began the slow process of sterilization and dehydration of the body, accomplished by osmosis with dry natron. Resterilization of the cavities, perfuming, closing the incision, and wrapping the body with linen and with beeswax completed the process. Molten resin was used to seal the body and its wrappings, providing a barrier against insects and anaerobes.（6）混合型段落，很多时候，一个单独的段落是由多种方法结合而成的。例如下面这个段落，由定义、分析和说明三个部分组成逻辑顺序。流畅是用来描述一段文字从一个想法转移到另一个想法的方式。这种转移既发生在段落内部，也发生在段落之间。提高段落内流畅性的最佳方式就是体现段落内句子的联系，例如，有意识地重复关键词。通过重复关键词或关键词的同义词来强调重点，可以增强整个段落的连贯性。在下面的段落中，关键词Canadian，nation和communication的重复使得整个段落清晰流畅。It’s perhaps not surprising that Marshall McLuhan, the most influential communications expert of the twentieth century, was a Canadian. As a nation, we have been preoccupied with forging communication links among a sparse, widespread population. The old Canadian one-dollar bill, with its line of telephone poles receding to the distant horizon, illustrates this preoccupation. Year after year we strive to maintain a national radio and television broadcasting system in the face of foreign competition. We have been aggressive in entering the international high technology market with our telecommunications equipment.虽然有意地重复关键词是一种有用的方式，但要避免重复整个句子或概念。特别要注意的是，不要在段落结束时提出与主题句相同的观点，这种重复会阻碍段落的逻辑发展。有策略地使用代词，比如it, they等，只要它们和特定的名词有明确的联系，就放在段落开头，例如下面的段落。Minois concluded his overview by suggesting that old age was something “which the early Middle Ages were decidedly not concerned about” (1989: 155). This lack of concern was not because of the absence of old people, for Minois believed that “once they had survived to their 20th year, the men [sic] ... could expect to live as long as we do” (1989:149). Rather, he suggested, old people “played only a negligible social role and were dependent on the care of their families”—in effect they were marginalised by the society of the time (1989: 149).专门的连接词也可以把句子联系在一起，但要符合逻辑。
also | in other words | in addition |
for example | moreover | more importantly |
but | on the other hand | however |
instead | yet | in contrast |
although | nevertheless | in spite of [something] |
thus | therefore | ultimately |
in conclusion | finally | so [informal] |
段落的长度取决于段落的需要。通常，段落在一页的三分之一到三分之二之间，注意这里的段落是双倍行距。
一连串的长段落会使论文变得晦涩难懂，读起来不舒服。一页最好有两个或两个以上的段落。一个长段落可以在一个有逻辑转折的位置添加一个主题句，使段落的主题更加清晰。
注意：只有两到三句话的短段落会使学术写作显得支离破碎，最好将相同主题的段落合并，或者扩展短段落成为长段落。
本期主要介绍了SCI论文的段落，相信你看完本文一定会发现，一篇讲究的SCI论文的形成，离不开每一个讲究的段落！笔者将会持续给大家提供SCI论文写作技巧干货，请大家锁定“投必得学术”。
