一个段落不是杂乱无章的，而是有机的组合，句子的排列顺序必须合乎逻辑，从一个句子到另一个句子的过渡必须流畅(smooth)，这就是连贯性(coherence)......

连贯性(coherence)

连贯性包括意连和形连两个方面，前者指的是内在的逻辑性，后者指的是使用转换词语。当然这两者常常是不可分割的。只有形连而没有意连，句子之间就没有内在的有机的联系;反之，只有意连而没有形连，有时行文就不够流畅。

1)意连

段落中句子的排列应遵循一定的次序，不能想到什么就写什么。如果在下笔之前没有构思，边写边想，写写停停，那就写不出一气呵成的好文章来。下面介绍几种常见的排列方式。

A.按时间先后排列(chronological arrangement)

We had a number of close calls that day. When we rose, it was obviouslylate and we had to hurry so as not to miss breakfast; we knew the dining roomstaff was strict about closing at nine o'clock. Then, when we had been drivingin the desert for nearly two hours ----- it must have been close to noon ----the heat nearly hid us in; the radiator boiled over and we had to use most ofour drinking water to cool it down. By the time we reached the mountain, it wasfour o'clock and we were exhausted. Here, judgement ran out of us and we startedthe tough climb to the summit, not realizing that darkness came suddenly in thedesert. Sure enough, by six we were struggling and Andrew very nearly went downa steep cliff, dragging Mohammed and me along with him. By nine, when the windhowled across the flat ledge of the summit, we knew as we shivered together forwarmth that it had not been our lucky day.

本段从"rose"(起床)写起，然后是吃早餐("not to miss breakfast", "closing at nineo'clock")，然后是"close to noon"，一直写到这一天结束("By nine--")。

B.按位置远近排列(spatial arrangement)。例如：From a distance, it looked like a skinnytube, but as we got closer, we could see it flesh out before our eyes. It wastubular, all right, but fatter than we could see from far away. Furthermore, wewere also astonished to notice that the building was really in two parts: apagoda sitting on top of a tubular one-story structure. Standing ten feet away,we could marvel at how much of the pagoda was made up of glass windows. Almosteverything under the wonderful Chinese roof was made of glass, unlike the tubethat it was sitting on, which only had four. Inside, the tube was gloomy,because of the lack of light. Then a steep, narrow staircase took us up insidethe pagoda and the light changed dramatically. All those windows let in a floodof sunshine and we could see out for miles across the flat land.

本段的写法是由远及近，从远处("from a distance")写起，然后"get closer"，再到(" ten feetaway")，最后是"inside the pagoda"……当然，按位置远近来写不等于都是由远及近。根据需要，也可以由近及远，由表及里等等。

C.按逻辑关系排列(logical arrangement)

a.按重要性顺序排列(arrangement insgroupsof importance)

If you work as a soda jerker, you will, of course, not need much skill inexpressing yourself to be effective. If you work on a machine, your ability toexpress yourself will be of little importance. But as soon as you move one stepup from the bottom, your effectiveness depends on your ability to reach othersthrough the spoken or the written word. And the further away your job is frommanual work, the larger the organization of which you are an employee, the moreimportant it will be that you know how to convey your thoughts in writing orspeaking. In the very large business organization, whether it is the government,the large corporation, or the Army, this ability to express oneself is perhapsthe most important of all the skills a man can possess.

这一段谈的是表达能力，它的重要性与职业，身份有关，从"not need much skill"或"of littleimportance"到"more important"，最后是"most important"。

b.由一般到特殊排列(general-to-specific arrangement)

If a reader is lost, it is generally because the writer has not beencareful enough to keep him on the path. This carelessness can take any number offorms. Perhaps a sentence is so excessively cluttered that the reader, hackinghis way through the verbiage, simply doesn't know what it means. Perhaps asentence has been so shoddily constructed that the reader could read it in anyof several ways. Perhaps the writer has switched tenses, or has switchedpronouns in mid-sentence, so the reader loses track of when the action tookplace or who is talking. Perhaps sentence B is not logical sequel to sentence A---- the writer, in whose head the connection is clear, has not bothered toprovide the missing link. Perhaps the writer has used an important wordincorrectly by not taking the trouble to look it up. He may think that"sanguine" and "sanguinary" mean the same thing, but the difference is a bloodybig one. The reader can only infer what the writer is trying to imply.

这一段谈的是a writer's carelessness，先给出一个generalstatement作为主题句，然后通过5个"perhaps"加以例证。

c.由特殊到一般排列(specific-to-general arrangement)

I do not understand why people confuse my Siamese cat, Prissy, with the oneI had several years ago, Henry. The two cats are only alike in breed. Prissy, aquiet, feminine feline, loves me dearly but not possessively. She likes to keepher distance from people, exert her independence and is never so rude as to beg,lick, or sniff unceremoniously. Her usual posture is sitting upright, eyesclosed, perfectly still. Prissy is a very proper cat. Henry, on the other hand,loved me dearly but possessively. He was my shadow from morning till night. Heexpected me to constantly entertain him. Henry never cared who saw him doanything, whether it was decorous or not, and he usually offended my friends insome way. The cat made himself quite comfortable, on the top of the television,across stranger's feet or laps, in beds, drawers, sacks, closets, or nooks. Thedifference between them is imperceptible to strangers.

本段的主题句是段首句，它仅提出一个问题：为什么两只猫会被搞混。然后对两者进行比较，末句才下结论。

2)形连

行文的逻辑性常常要靠适当的转换词语及其他手段来实现。请读下面这一段文字并找出文中用以承上启下的词语：雅思需要多少词汇量

Walter's goal in life was to become a successful surgeon. First, though, hehad to get through high school, so he concentrated all his efforts on hisstudies --- in particular, biology, chemistry, and math. Because he workedconstantly on these subjects, Walter became proficient in them; however, Walterforgot that he needed to master other subjects besides those he had chosen. As aresult, during his junior year of high school, Walter failed both English andLatin. Consequently, he had to repeat these subjects and he was almost unable tograduate on schedule. Finally, on June 6, Walter achieved the first step towardrealizing his goal.

本文中起承上启下的词语有两种，一种是转换词语(transitional words orphrases)，另一种是起转换作用的其他连接手段(linking devices)。前者依次有：first, though, so, inparticular, and, because, however, besides, as a result, both…and, consequently,and, finally.后者依次是：he, he, his, his, he, these, them, he, those, his, he, these,his.本段1有词汇105个，所使用的转换词语及其他连接用语共26个词，约占该段总词汇量的四分之一。由此可见，掌握好transitions不仅对行文的流畅(smoothness)有益，而且对于学生在规定时间内写足所要求的字数也是不无好处的。

一个段落里如果没有transitions也就很难有coherence了.我们看下面一个例子：

Speaking and writing are different in many ways. Speech depends on sounds.Writing uses written symbols. Speech developed about 500 000 years ago. Writtenlanguage is a recent development. It was invented only about six thousand yearsago. Speech is usually informal. The word choice of writing is often relativelyformal. Pronunciation and accent often tell where the speaker is from.Pronunciation and accent are ignored in writing. A standard diction and spellingsystem prevails in the written language of most countries. Speech relies ongesture, loudness, and rise and fall of the voice. Writing lacks gesture,loudness and the rise and fall of the voice. Careful speakers and writers areaware of the differences.

本段中除了第6句开头出现一个起过渡作用的"it"之外，没有使用其他的过渡词语.这样，文中出现许多重复的词语，全段读起来也显得生硬而不自然。如果加上必要的过渡词语来修饰的话，这一段就成了下面一个流畅连贯的段落：

Speaking and writing are different in many ways. Speech depends on sounds;writing, on the other hand, uses written symbols. Speech was developed about 500000 years ago, but written language is a recent development, invented only aboutsix thousand years ago. Speech is usually informal, while the word choice ofwriting, by contrast, is often relatively formal. Although pronunciation andaccent often tell where the speaker is from, they are ignored in wiring becausea standard diction and spelling system prevails in most countries. Speech relieson gesture, loudness, and the rise and fall of the voice, but writing lacksthese features. Careful speakers and writers are aware of the differences.

有损连贯性的几种情况：

考生在写作中经常出现下面几种错误：

1)不必要的改变时态，比如：

In the movie, Robert Redford was a spy. He goes to his office where hefound everybody dead. Other spies wanted to kill him, so he takes refuge withJulie Christie. At her house, he had waited for the heat to die down, but theycome after him anyway.

2)不必要的改变单复数，比如：

Everybody looks for satisfaction in his life. They want to be happy. But ifhe seeks only pleasure in the short run, the person will soon run out ofpleasure and life will catch up to him. They need to pursue the deeper pleasureof satisfaction in work and in relationships.

3)不必要的改变人称，比如：

Now more than ever, parents need to be in touch with their children'sactivities because modern life has the tendency to cause cleavages in thefamily. You need to arrange family like it so that family members will do thingstogether and know one another. You need to give up isolated pleasures of yourown and realize that parents have a set of obligations to sponsor togethernessand therefore sponsor knowledge.

因此写作中，一定要注意时态，人称以及数的变化是否正确，要注意保持一致。