有效段落的一个重要特征是统一性。一个统一的段落从头到尾都坚持一个主题，每个句子都有助于该段落的中心目的和主要思想。

但是一个强有力的段落不仅仅是一组松散的句子。这些句子需要清楚地连接起来，以便读者能够跟上，认识到一个细节是如何引导下一个细节的。一个句子连接清晰的段落被认为是连贯的。

关键词重复

在段落中重复关键词是实现衔接的重要技巧。当然，粗心或过度的重复是无聊的，也是混乱的根源。但是，如下面的段落所示，这种技巧可以巧妙地、有选择性地使用，将句子组合在一起，并将读者的注意力集中在一个中心思想上。

We Americans are a charitable and humane people: we have institutions devoted to every good cause from rescuing homeless cats to preventing World War III. But what have we done to promote the art of thinking? Certainly we make no room for thought in our daily lives. Suppose a man were to say to his friends, "I'm not going to PTA tonight (or choir practice or the baseball game) because I need some time to myself, some time to think"? Such a man would be shunned by his neighbors; his family would be ashamed of him. What if a teenager were to say, "I'm not going to the dance tonight because I need some time to think"? His parents would immediately start looking in the Yellow Pages for a psychiatrist. We are all too much like Julius Caesar: we fear and distrust people who think too much. We believe that almost anything is more important than thinking. (Carolyn Kane, from "Thinking: A Neglected Art." Newsweek, December 14, 1981)

注意，作者使用同一单词的各种形式think、thinking、thinking来连接不同的例子，并强化段落的主要思想。（为了让初露头角的修辞学家受益，这一装置被称为Polytoton。）

关键词和句子结构的重复

在我们的写作中，实现衔接的一个类似方法是重复一个特定的句子结构以及一个关键词或短语。虽然我们通常会尝试改变句子的长度和形状，但有时我们可能会选择重复一个结构来强调相关概念之间的联系。

以下是肖伯纳（George Bernard Shaw）戏剧《结婚》中结构重复的一个简短例子：

There are couples who dislike one another furiously for several hours at a time; there are couples who dislike one another permanently; and there are couples who never dislike one another; but these last are people who are incapable of disliking anybody.

注意Shaw对分号（而不是句号）的依赖如何增强了这篇文章中的统一感和凝聚力。

延长重复

在极少数情况下，强调性重复可能超出两到三个主要从句的范围。不久前，土耳其小说家奥汉·帕穆克（Orhan Pamuk）在其诺贝尔奖演讲《我父亲的手提箱》（My Father’s手提箱）中提供了一个扩展重复的例子（特别是一种称为回指的手段）：

The question we writers are asked most often, the favorite question, is: Why do you write? I write because I have an innate need to write. I write because I can’t do normal work as other people do. I write because I want to read books like the ones I write. I write because I am angry at everyone. I write because I love sitting in a room all day writing. I write because I can partake of real life only by changing it. I write because I want others, the whole world, to know what sort of life we lived, and continue to live, in Istanbul, in Turkey. I write because I love the smell of paper, pen, and ink. I write because I believe in literature, in the art of the novel, more than I believe in anything else. I write because it is a habit, a passion. I write because I am afraid of being forgotten. I write because I like the glory and interest that writing brings. I write to be alone. Perhaps I write because I hope to understand why I am so very, very angry at everyone. I write because I like to be read. I write because once I have begun a novel, an essay, a page I want to finish it. I write because everyone expects me to write. I write because I have a childish belief in the immortality of libraries, and in the way my books sit on the shelf. I write because it is exciting to turn all life’s beauties and riches into words. I write not to tell a story but to compose a story. I write because I wish to escape from the foreboding that there is a place I must go but— as in a dream— can’t quite get to. I write because I have never managed to be happy. I write to be happy. (The Nobel Lecture, 7 December 2006. Translated from the Turkish, by Maureen Freely. The Nobel Foundation 2006)

我们的论文采样器中出现了两个著名的延长重复的例子：朱迪·布雷迪的文章“为什么我想要一个妻子”（包括在论文采样器的第三部分）和小马丁·路德·金博士的“我有一个梦想”演讲中最著名的部分。

最后提醒：应该避免不必要的重复，因为这只会让我们的写作变得杂乱无章。但是仔细地重复关键词和短语是形成连贯段落的有效策略。