行文逻辑是指一段话或者一篇文章根据一定的特定的顺序和构段方式使其有条理性、清晰性。常用逻辑分为两种（1）按照一定顺序分为:说明顺序、时间顺序、空间顺序、事件顺序（2）按照构段方式分为：总分关系、并列关系、因果关系、承接关系、转折关系。

对于一段话或者一篇文章，都要有一定的行文逻辑，这样才能使文章有条理性、清晰性。常用的逻辑分为两种：（1）说明顺序：空间、时间、事情的发展等（2）构段方式：总分、分总、承接、并列等。

写好文章，首先要抓住说明对象的特征，其次最重要的是运用合理的说明顺序。所谓合理的说明顺序，是指能充分表现事物或事理本身特征的顺序，也是符合人们认识事物、事物规律的顺序。常见的说明顺序有：时间顺序、空间顺序、逻辑顺序等。正确的顺序能正确地理清文章思路，能帮助读者理解，在说明文等叙述性较强的文体中，说明顺序更是必不可少的。

即按照事理发展过程的先后来介绍某一事物的说明顺序。凡是事物的发展变化都离不开时间，如说明生产技术、产品制作、技术方法、历史发展、文字演变、人物成长、动植物生长等等，都应以时间为序。比如中学课本中有一篇《景泰蓝的制作》，它就是按照景泰蓝的制作过程中“做胎――掐丝――烧制――点蓝――烧蓝――打磨――镀金”的时间顺序来说明的。

即按照事物空间存在的方式，或从外到内，或从上到下 ，或从整体到局部来加以介绍，这种说明顺序有利于全面说明事物各方面的特征。一般说明某一静态实体（如建筑物等），常用这种顺序。如课本中的《核舟记》就是按照船体――船头――船尾――船背的空间顺序来写的；《故宫博物馆》按照先总后分的顺序，先概括说明故宫建筑物的总体特征，然后再具体介绍太和门――太和殿――中和殿――保和殿――乾清宫……御花园，而在介绍每一座建筑物的时候，则又按照先外后内、先上后下的顺序。这样安排合乎人们观察事物的习惯，是最合理的顺序。

即按照事物、事理的内在逻辑关系，或由个别到一般，或由具体到抽象，或由主要到次要，或由现象到本质，或由原因到结果,递进,或概括到具体,或特点到用途,或由整体到局部一一介绍说明。不管是实体的事物，如山川、江河、花草、树木、器物等，还是抽象的事理，如思想、观点、概念、原理、技术等，都适用于以逻辑顺序来说明。如课本中的《死海不死》、《向沙漠进军》，都是运用逻辑顺序来说明事物的。凡是阐述事物、事理间的各种因果关系或其他逻辑关系，按逻辑顺序写作最为适宜。

构段方式是指文章的段落组成之间的逻辑关系，构段是文章的基础。构段要完整统一，一是段意要单一而不杂乱。人们把只包含一个意思的段落，叫作单义段。要提倡组织单义段，一段集中表达一个意思，不要把与本段段意无关的内容写进同一段落里去。二是段意要完整而不残缺。就是一个段落要把一个意思说完整，不要一个意思硬拆成两段说。此外，还要注意段与段之间的联系与衔接。要用好关联词语，写好过渡句、段，使文章承上启下，前后照应，首尾圆台，浑然一体。

几种常见的构段方式：

1．总分关系：先用一个概括性的句子总述全段的主要内容，再围绕这句话从几个不同方面加以分述。它包括：①先分后总 ②先总后分 ③总—分—总

2．并列关系：一段话中，围绕一个意思，分别写了几个方面，句与句之间没有主次之分，只是并列存在

3．因果关系：一般一段话中有两层意思：一层写原因，另一层写结果，两者构成因果关系，有的先因后果，有的先果后因。

4．承接关系：整个自然段按事情发展顺序，有的按时间先后顺序或方位顺序组织材料的

5．转折关系：段内层次的意思有肯定与否定之别，并有明显的转折词“可是”或“但是”等分开。

Passage 1

A strict vegetarian is a person who never in his life eats anything derived from animals. The main objection to vegetarianism on a long-term basis is the difficulty of getting enough protein—the body-building element in food. (41) . You are glad when the fast is over and you get your reward of a succulent meat meal.

Proteins are built up from approximately twenty food elements called “amino-acids,” (42) . This means you have to eat a great deal more vegetable than animal food in order to get enough of these amino-acids. A great deal of the vegetable food goes to waste in this process and from the physiological point of view there is not much to be said in favor of life-long vegetarianism.

The economic side of the question, though, must be considered. Vegetable food is much cheaper than animal food. (43) . In fairness, though, it must be pointed out that vegetarians claim they need far less than 70 grams of protein a day.

Whether or not vegetarianism should be advocated for adults, (44) . A lacto-vegetarian diet, which includes milk and milk products such as cheese, can, however, be satisfactory as long as enough milk and milk products are consumed. Meat and cheese are the best sources of usable animal protein and next come milk, fish and eggs.

(45) . When cooking vegetables, however, the vitamins, and in particular the water-soluble vitamin C, should not be lost through over-cooking.

[B] Slow and careful cooking of meat makes it more digestible and assists in the breaking down of the protein content by the body.

[C] If you have ever been without meat or other animal foods for some days of weeks (say, for religious reasons) you will have noticed that you tend to get physically rather weak.

[D] The most common deficiencies in Western diets today are those of vitamins. The answer is variety in food. A well-balanced diet having sufficient amounts of milk, fruit, vegetables, eggs, and meat, fish or fowl (i.e. any good protein source) usually provides adequate minimum daily requirements of all the vitamins.

[E] However, since only a small proportion of the vegetable protein is useful for body-building purposes, a consistent vegetarian, if he is to gain the necessary 70 grams of protein a day, has to consume a greater bulk of food than his digestive organs can comfortably deal with.

[F] which are found more abundantly in animal protein than in vegetable protein.

[G] it is definitely unsatisfactory for growing children, who need more protein than they can get from vegetable sources.

Passage 2

A massive pool of warm ocean water is causing changes in the atmosphere that could produce unusual weather around the world in the next few months, the US National Weather Service reported on Monday.

(41) . Currently the phenomenon is marked by a warm pool of water along the equator extending from the international date line nearly to the coast of South America. That water is nearly 4 degrees Fahrenheit above normal, explained Vernon Kousky of the climate center.

(45) . Overall damage was estimated at between $ 2 billion and 8 billon by a United Nations analysis and the death toll topped 1,500 worldwide.

That doesn't mean that the disruption will be as great this time, however. A mild El Nino in 1986-1987 was barely noticed, for example.

[A] This warm water “'spreads almost a quarter of the way around the globe. So it's massive and it has an impact on our weather. It has a global influence...because it disturbs the atmosphere,” said Dave Rodnehuis, director of the climate center.

[B] The strong El Nino of 1982-1983 was blamed for worsening the devastating drought in Africa, causing a series of severe winter storms to come ashore in California, spawning the first typhoon to strike French Polynesia in 75 years—followed by five more in five months—deluging Peru and Ecuador with torrential rains and promoting the worst drought in two centuries in Australia.

[C] Details of its causes are not fully understood, but when it occurs, unusually warm air can be pumped into Canada, Alaska and the northern United States.

[D] As a result of this phenomenon, known as El Nino, more rainfall than normal is likely this winter across some areas of the United States, with unusually warm or cold weather in other parts of the country.

[E] Every once in a while the reasons for discouragement about the human prospect pile up so high that it becomes difficult to see the way ahead, and it is then a great blessing to have one conspicuous and undeniable good thing to think about ourselves, something solid enough to step onto and look beyond the pile.

[F] Because the changes tended to be first noticed around Christmas, the phenomenon was given the name El Nino, which is Spanish for child, a term often used to refer to the baby Jesus.

[G] Lying, then is stressful, even when we do it for protection, or relief, or escape, or profit, or just for the pure pleasure of lying and getting away with it. It is a strain, distressing enough to cause the emission of signals to and from the central nervous system warning that something has gone wrong. It is, in a pure physiological sense, an unnatural act.

可以把一个百科词条看作一篇文章，任何一篇文章都应该有合理的逻辑。只有满足了这一点的词条才是可读的。

有逻辑的叙述

正文能按逻辑阐述词条内容

百科词条的内容安排应该符合认识事物的一般逻辑。

百科词条中常用的叙述逻辑包括：从主要到次要，从整体到部分，从一般到特殊，从原因到结果，从概念到应用，时间顺序，空间顺序等。

如人物类词条，一般应按从主要到次要的顺序介绍其概述、生平事迹、主要成就、主要作品、家庭关系、轶闻等等，不宜先介绍轶闻，最后介绍生平事迹；科学概念类词条，一般应按从概念到应用的顺序介绍其概述、基本定义、主要原理/构成、研究历史、应用场景等，不宜先介绍应用场景，最后介绍基本概念；集合类词条，如唐宋八大家，一般应按从整体到部分的顺序，首先介绍其概述、背景、文学地位等总述内容，而后分别简介八大家，不应先介绍人物后介绍八大家的文学地位。

有的叙述逻辑常见于文学作品中，但不建议在百科词条中使用。如，从次要到主要，从特殊到一般，从应用到概念等。

概述能概括词条主要内容

对于达到一定长度（约一千字）以上的词条，有必要添加名片。概述是名片的主要组成部分。

概述是词条内容的简介，用户读过了概述就应该了解了词条的基本内容。

概述至少应该包含以下的内容：定义词条的主题，概括词条中最重要的地方（包括任何明显的争议），解释为何词条所介绍的东西是有趣的或值得注意的。

关于概述的更多内容，请参阅使用名片。

合理划分内容层级

使用目录划分内容层级可以令百科词条条理清晰，排版美观，对词条可读性有很大的价值。层级划分应遵循金字塔状的层级结构，将词条内容划分为合理的几个部分（一级目录），每个部分又可继续划分为小部分（二级目录）。

如帝王类词条：

以下列出划分内容层级时应该遵循的一些原则。

金字塔结构基本原则

金字塔结构应遵循以下的基本原则——各个组成部分彼此相互独立不重叠，但是合在一起完全穷尽不遗漏。

如上述的帝王类词条结构中的各个部分就符合这一基本原则。相反，如“曹操”词条中，“个人作品”和“文学造诣”有相互重叠，不适合同时出现在一级目录中，“文学造诣”应是“个人作品”一级目录下的一个二级目录。

同一级目录应建立在一个维度上

同一级目录的划分应建立在同一个维度上，存在一定的并列关系。如面向同一个问题的不同侧面，或列举几个同级别的组成部分等。

如“人物生平”“为政举措”“人物评价”等一级目录都是帝王的一个侧面，而“为政举措”一级目录下的“政治”“军事”“经济”等二级目录都是为政举措的一个部分。不宜将不同维度的内容放在同一级目录之下，如将“家世”“兄弟姐妹”“后妃”“子女”等内容都列为一级目录就是不合适的。

同一级目录符合叙述逻辑

各个一级目录之间，每个一级目录下的二级目录之间，都应该符合叙述逻辑，如从主要到次要，从整体到部分，从一般到特殊，从原因到结果，从概念到应用，时间顺序，空间顺序等。

如“人物生平”一级目录下的二级目录按时间顺序叙述，“人物评价”一级目录下的二级目录按从总体到部分的顺序叙述。

内容详细程度不超过三级

一般来说，百科词条内容的详细程度以不超过三级为宜。内容较少的词条可仅使用一级目录或不使用目录，内容较多的词条可使用二级目录，每个二级目录下可再展开几个子主题（第三级）进行论述，每个子主题以几十到几百字为宜；但每个子主题不宜再拆分为几个主题分别论述，也不宜有过长的篇幅。

例如，当撰写“刘备”词条时，“人物生平”一级目录下“早年经历”二级目录的内容，大致包含“征讨黄巾”“徐州自立”“依附刘表”“赤壁之战”“征服巴蜀”等几个子主题（第三级），每个子主题以几十至几百字进行简介为宜；“家庭成员”一级目录下“后妃”二级目录的内容，包含甘夫人、糜夫人、孙夫人、穆皇后几个子主题（第三级），每个子主题以几十至几百字进行简介为宜，不宜用大篇幅介绍各位夫人的生平事迹等。

避免不合理的叙述逻辑

避免事无巨细

百度百科内容，应是对主题进行摘要性总结，而非无节制的追求细节。哪些内容应该写进词条，哪些不应该，可参阅完整的词条结构。

例如，一个电视剧导演的词条中不应该列出其每部作品的演员表、分集剧情等；一个演员的词条中不应该列出他/她参加的每一期综艺节目。

避免喧宾夺主

百度百科内容应主次分明，使读者更清晰的了解一个主题，避免因主次不清对读者造成误导。

例如一首诗歌，其作者信息是辅助读者理解诗歌本身的，若过多着笔于作者介绍，可能会误导读者去阅读作者信息，而忽略了诗歌本身；一名艺人的词条中不应用大篇幅记录其某一次普通采访的内容。

一般来说，如果在词条中需要介绍与之相关的另一词条，其内容篇幅不应超过一般的概述长度。例如《星球大战》词条中关于导演乔治卢卡斯的介绍，“太阳系”词条中关于各行星的介绍等，对其进行概述即可，无需大篇幅描写。可以使用主词条模块链接相关的词条。