经常有同学抱怨“考场上写英语作文感到无从下笔，每次读完题目后头脑一片混乱，而且总是写不清楚”。问题出现在哪些地方呢？
我们先来看看文章的评判标准。一般情况下，我们可以通过这几个标准来衡量一篇文章的优劣：词汇的丰富与准确性，语法的准确性，文章的连贯与流畅度，观点是否清晰扣题，论证是否严谨有力。
对大部分人来说，词汇和语法并不是最大的问题，多阅读多练习，假以时日，总可以慢慢掌握。实际上，在英文写作中最让人头疼的往往是后面几项：观点的提出以及论证，文字的衔接和耦合。
文章要做到连贯流畅，观点清晰，论证有力，仅仅靠背单词和学语法是不够的，因为它还涉及到一个更深层次的问题：逻辑思维能力。
写作活动是一种严密而有序的逻辑思维过程。很多作文中出现的表达混乱，层次不清等问题，往往是写作时逻辑思维混乱导致的。还没想清楚就下笔，写出来的东西自然不会清晰到哪里去。
那我们应该要怎样做，才能提高逻辑思维能力，写出清晰严谨的文章呢？
之前一直有这样的说法“英语是一门逻辑性很强的语言”，为什么这么说呢？
因为仔细观察你会发现，英语在遣词造句上是遵循严密的的逻辑形式的：用词上要求人称、数、格的一致；句子有严谨的主谓结构，多用关联词语，重视形式的对应和显性衔接。而在语篇中多突出主题句，直线式地展开段落。
对于写作来说，一篇好的文章要遵循句子和句子之间，段落和段落之间的衔接和连贯。一篇好文章并不是句子的机械堆砌，而是一个有机整体，句子和句子之间是存在严谨的逻辑关系的。举个例子，下面是一篇常见的说明文段落：
AIDS seems to follow a pattern of recognizable symptoms. First, after being exposed to the virus, the AIDS patients tend to complain of a fever, sore throat, sore muscles,and diarrhea. Then there seems to be a dormant period ,which can last for three years or longer. Finally, after this period, more serious symptoms begin to emerge.
仔细阅读之后会发现，文章中的句子之间在逻辑上环环相扣，每一个都不可或缺。如果句子之间的衔接没做好，写出来的文章可能会是这样的：
Every summer, I go traveling with my family or my best friends. When the new term comes, I will surprisingly find my oral English is much improved. So I firmly believe book is not only the source of knowledge.
上面的句子读起来感觉很奇怪，为什么？因为句子与句子之间并没有一个很好的逻辑关系："go traveling with my family" 与后面的"my oral English is much improved" 并没有必然联系，逻辑上讲不通。
除了句子的衔接外，段落与段落之间的衔接也非常重要。这一点在经济学人等外刊文章上体现得很好，比如这篇文章The weaker sex, 段落的结构非常清晰，开头都有主题句来引领全段，而且段落与段落之间是层层递进的关系。
1. What can be done? Part of the solution lies in a change in cultural attitudes.
2. Policymakers also need to lend a hand, because foolish laws are making the problem worse.
3. Even more important than scrapping foolish policies is retooling the educational system, which was designed in an age when most men worked with their muscles.
4. More generally, schools need to become more boy-friendly.
从上面可以看到，要写出逻辑清晰的文章，我们要特别注意句子以及段落的衔接和连贯。这就要求我们要用好连接词以及语义承接。
在写作中常见的连接词有"because, as, while, if, however, therefore, although, similarly, consequently, nevertheless "等，它们属于“明连接”。
语义承接则是通过上下文之间的承接关系来自然行文，比如通过指示代词、人称代词等对前一句中出现过的内容进行指代，或者对前一句话中出现的关键词进行转述，解释，从而形成自然的承接关系。语义承接属于“暗承接”。
下面这篇雅思9分作文片段就很好地体现了连接词以及语义承接的效果（仔细体会加黑以及带下划线的单词，感受一下连接词的效果）。
I tend to agree that young children can be negatively affected by too much time spent on the computer everyday. This is partly because sitting in front of a screen for too long can be damaging to both the eyes and the physical posture of a young child, regardless of what they are using the computer for.
The main concern is about the type of computer activities that attract children. These are often electronic games that tend to be very intense and rather violent. The player is usually the "hero" of the game and too much exposure can encourage children to be self-centred and insensitive to others.
上面的作文片段中，"This" 用来指代"I tend to agree..." 一整句的内容，连接词"because"用来连接从句说明原因，"regardless of" 后面连接名词性从句做进一步说明。"These"用来指代上一句中出现的 "computer activities"，用定冠词"the"修饰的"player" 和 "game" 则与上一句呼应，指代游戏中的玩家和游戏。
由此可以看出，通过用好连接词以及语义承接的方式，我们可以将句子甚至段落有机联系起来，使之符合逻辑。
事实上，衔接和连贯性(Coherence and Cohesion)一直是雅思写作中的一个重要评分标准，雅思官方也给出了一个指导视频：IELTS Writing 雅思写作连贯性（http://v.qq.com/boke/page/u/0/4/u0176w0hz94.html)
由于种种原因，我们的中学教育甚至大学教育都没有对学生进行系统的逻辑学训练，这也在一定程度上对写作造成了影响。基本逻辑学知识的缺失会造成写作中语言不通，层次混乱，主题不明确等问题。要写出思维严谨，脉络清晰的文章，我们必须掌握基本的逻辑学规律。
具体到英文写作中，常用的逻辑学基本规律主要有排中律，同一律，矛盾律这三种。
排中律是指：文章的立意要明确，旗帜鲜明，千万不要和稀泥。比如像这样的作文题目 "Some people think that students should go to boarding schools instead of living at home. Do you agree or disagree?" 我们应该在文章中明确给出自己的意见：赞同上寄宿学校或者反对，而不是模棱两可，观点不清。
同一律是指：在思考过程中，使用的概念或判断必须始终不变，保持同一。在英文写作中，要确保文章的立意和体裁符合要求并且在行文中始终如一，语体风格得体。比如下面的例子：
Judging from the current tendency, I am inclined to believe that traditional shopping will disappear gradually and the reasons are as follows: For one thing, the online shopping can bring convenience to people’s life ... For another, the merchandizes in online shops are much cheaper than that in those real shops because... Everybody tends to choose the online shopping in this case.
读起来是不是感觉有点怪？因为它出现了前后不一致的问题，前半部分给出的论点是传统购物会逐渐消失，后面的论证过程却在说网购的好处，两者失去了同一性，不能衔接。
矛盾律是指：文章论述必须首尾相贯，避免出现自相矛盾，跑题离题的现象。比如对" Asking students to evaluate their teachers is a good idea" 这样的题目，文章中应该阐述学生评分带来的好处，而不应该把阐述重点放在学生评分带来的坏处上。
以上三个基本规律虽然看起来很简单，但在实际写作过程中却经常有人违反，下次写作的时候不妨仔细检查一下，看看有没有遵循这几个规律。
当然，逻辑学远不止上面提到的三种规律那么简单，它是一门非常精深的学科，建议有时间的同学去系统学习一下逻辑学的著作。这里推荐一本入门书籍 How To Think Logically。
事实上，我们不能把一件事说清楚，很多时候并不是语言技巧的问题，而是在于，我们对这件事情不够了解，知识储备不够多。设想一下，让你写文章分别讨论自己最擅长的领域和最不擅长的领域，哪一个会写得更有条理？
如果没有基本的知识储备，空谈语言技巧和逻辑思维方法并没有意义。假如你不知道Uber,Lyft或者Airbnb, 碰到“共享经济”(sharing economy)这类话题时可能会无从下手——清晰的逻辑，有力的论证，一定是建立在对话题有足够多了解的基础之上的。所以才有这句话“读书破万卷，下笔如有神”。
更现实一点，对于考场作文来说，常见的话题包括教育，科技，发展，媒体，政府，文化，环境，犯罪，全球化等，要写好这类文章，一定要对这些话题有足够多的了解。而了解它们最好的方法是通过大量的阅读，要广泛阅读关于这些题材的文章，积累起足够多的素材，肚子里有货才能写出东西来。
应该寻找什么样的阅读材料？外刊就是一个很好的选择。因为外刊文章（比如经济学人和卫报）往往篇幅适中，信息量大，所讨论的主题又与考场作文话题息息相关，非常适合用来做素材积累。可以留意一下自己对哪些话题最不熟悉，然后想办法通过阅读来积累素材。
在这里也推荐一本书，剑桥大学出版社的 English Vocabulary in Use Advanced。
这本书详细列出了常见的100个话题下可能出现的词汇以及表达。比如对于学习考试类的话题，它会列出"cram for exam,bury yourself in your books,know the subject inside out" 等地道的词语和表达，还有相关素材，写作文时可以直接用上。
目前这本书在国内比较难买到纸质版，价格也相对昂贵，不过网上可以找到电子版，感兴趣的同学可以去搜索下载。
除了积累素材之外，做一个积极的阅读者也很重要。“积极的阅读者”是指，在阅读中要学会多次重复，主动思考。
一篇外刊文章读一遍是不够的，至少要读上三遍五遍，在阅读的过程要不断思考：作者的观点是什么？他是怎样论述这个观点的？文章的结构是怎样的？段落与段落之间有哪些联系？有哪些衔接词？让我来写的话，我会怎么写？
阅读时多问自己一些这样的问题，并尝试着模仿这些优秀文章，这样才能不断提升。
要写出一篇脉络清晰，表述严谨的文章，除了词汇和语法基本功之外，还要有完备的逻辑思维能力，即在写作过程中要保持句子与句子之间，段落和段落之间的衔接和连贯性，同时应用逻辑学的基本规律比如排中律，同一律，矛盾律等对文章进行检查。
除此之外，知识储备也非常关键，平时要大量阅读，有意识地对各种话题进行素材积累，并学习优秀文章的篇章结构，思维模式，从而让自己的文章水平不断提升。
写作的六种逻辑结构
每一种写作，无论是求职信、申请信、新闻报道、科幻小说都有各自的结构。这种结构就是文章的骨架，额是文章的基本要素，在这个坚实的基础上你才能写出独特的文章。每个人都有骨架，但每个个体之所以独特，却是因为我们的肌肉、面部特征、身材、曲线、性格、甚至是服装和配饰。
还记得小学的时候老师布置的五段式作文吗？通常题目会是“我的暑假”：老师会要求你先一段介绍、3段文章主体和一段结论。而这种通用格式，是六种常见正式/非正式写作结构的根基。
Every piece of writing, whether it is a cover letter for a job application, a news article, or a fictional short story, has its own structure. Think of structure as the skeleton of a piece of writing. It is the bare bones of the piece, all connected to form a solid, uniform foundation upon which you, the writer and the creator, will build something unique. Humans, for example, all have nearly identical basic skeletons. However, it’s everything that goes on top of those skeletons-the muscles, the facial features, the shape, the curves, the personality, and even the clothes and accessories-that makes each human unique.
Remember being assigned five-paragraph essays on your first day back to grade school every fall? They’d usually be titled "What I Did This Summer," and they’d be assigned to have an introduction, three supporting paragraphs making up the body of the work, and a conclusion. This general format is the root of the six common writing structures that can be used for both formal and informal written communication.
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分类结构：在分类结构中，一系列同样重要的主题将被阐述。政治演说，如竞选演说，甚至国情咨文演说，都是分类结构的例子。求职信中你可能会使用类似的结构，因为你会描述使你成为这个职位理想人选的所有特质。
Categorical: In a categorical structure, a series of equally important topics are addressed. A political speech, like a campaign speech or even The State of the Union Address, is a good example of categorical writing. You might use a similar structure in a cover letter for a job application, in which you describe all of your traits that would make you an ideal candidate for the position.
2
评价结构：在评价结构中，一个问题会首先被引入，然后作者再进行利弊的权衡。在写电子邮件时，你可以使用一个评价结构来询问一个好朋友的建议。
Evaluative: In an evaluative structure, a problem is introduced, and thenpros and cons are weighed. You might employ an evaluative structure when writing an e-mail to ask a close friend for advice.
3
时间逻辑结构：当你的注意力更多地是真实地讲述故事而不是最终结果时，就采用时间顺序结构。想想笑话是怎么讲的：”三个家伙走进酒吧……“ 设置一系列事件来传递最后的Punchline（关键语、笑料）。同样的，大多数短篇故事和小说都是以时间顺序进行的。
Chronological: When your focus is more the actual telling of the story than the end result, employ a chronological structure. Think of joke telling. "Three guys walk into a bar…" sets up a sequence of events to deliver that final punch line. Similarly, most short stories and novels are written chronologically.
4
对比结构：对比结构类似于评价结构，但是这种结构用于要分析的目标有更多的层级需要衡量的情况。在准备辩论赛的辩论稿时，你可以用对比结构来阐述你的观点比对方的观点强的原因。你也可以用对比结构阐述你为什么觉得市议会提高当地税收的决定是不正确的。
Comparative: This structure is similar to evaluative, but it is used when there are more layers to the situation at hand that is being weighed. You might use a comparative structure if you were writing a speech for a debate team to explain the various reasons why you feel your point is stronger than your opponent’s. Or you might use a comparative structure to write a letter to the editor explaining all the reasons you disagree with the city council’s decision to raise local taxes.
5
顺序结构：顺序结构与时间逻辑结构相似，但是这种结构通常会包含一种指引性的语气和一步一步的过程的说明。如果你想要教别人怎么做巧克力千层蛋糕、或者怎么找到当地的住宿，你都应该用这种结构写作，用上“首先“、“然后”、“接着”、“最后”等词。
Sequential: This structure is similar to Chronological, but is normally employed with a how-to voice when a step-by-step process is being described. If you were going to write about how to make your famous chocolate layer cake, or how to get to a great bed-and-breakfast you discovered out in the country, you would write sequentially, using words like, "First," "Next," "Then," and "Finally" to clarify your instructions.
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因果结构：这个结构一看其来似乎跟对比结构相似，但这种结构里面不包含不同内容之间的比较，而是探讨一件事情的起因和结果。你可以用这种结构探讨空气污染的原因，或者写信说明你为什么要辞职。
Causal: This structure might at first glance seem similar to Comparative structures, but it differs in that it does not involve weighing options against one another. Instead, it discusses the causes and then the effects regarding a particular topic or issue in that order. You might use this structure if you were writing an article on how something has come about, such as the contributing factors to air pollution. Or you might employ this technique in a letter explaining why you have decided to resign from your job.
在知道了各种不同的写作逻辑结构之后，开始去关注你接触到的文章的“骨架”吧。无论是看报纸杂志或者网络文章，你都应该留意一下它们的基本论点都是怎么组织的。好的写作者会持续不断地关注自己所阅读的东西来磨练自己的技巧。
Now that you know about the different kinds of structures, start paying attention to the skeletons of all the pieces of writing around you. The next time you flip through a magazine in a doctor’s waiting room, or skim through a weekly e-newsletter that you subscribe to, or even read a letter from a friend, take some time to x-ray the writing and see how its bare bones are connected. Good writers hone their skills by being constantly aware of what they’re reading.
