18.1 正确句和有效句
18.1A 正确句（Correct Sentence）
1） 正确句是一个语法概念，即要求一个句子的语法正确（参见7.1A）。
2） 正确性也包括语音和词汇正确，如口语中音发错了，书面语中词语错了（包括拼法），就不算正确句子。这在前面14.2中可以看到种种例子。
18.1B 有效句 （Effective Sentence）
1） 有效句指一个句子能有效地达到交际目的。显然，有效句必须是正确句。语法上不正确的句子，或者是有发音错误，有时也可以交际，即对方能够理会意思，但有效性很不可靠，往往会造成误解，14.2B讲到的那个旅行者把cough说成cow的发音，造成交际障碍，就是一例。
2） 要实现句子的有效性，当然还涉及是否适合语境和对象等问题。我们这里仅从修辞角度讨论句子本身结构上应具备的基本要求。第七章所讨论的句式多样化，即适当安排长句和短句，简单句和复合句以及使用一些具有修辞特色的句式，都是为增强句子的表达效果。下面再分别讨论对句子结构的3项修辞要求：句子的一致，句子的连贯和句子的强调。
18.2 句子的一致（Sentence Unity）
18.2A 句子一致的含义
1） 一致性是指句子所表示的思想是一个完整的统一体。例如：
Jane sat down, picked up her pen and started to write her composition:
“I got up early. Mom told me that there was always traffic jam and our car was a little bit too old and we need buy a new one.”
例中Jane的作文的开头两句话就不够一致：第一句意思欠完整，需补上动作发生的时间；第二句所表示的思想不统一，因为没有讲明两个分句之间的联系，也同第一句割裂，故它们没有形成一个完整的统一体。
2） 一致性是对句子结构的首要要求，全句使用的词语都要紧密地围绕一个中心思想，凡未达到这项要求的句子都应改写。例如对上面例子中那个学生的作文可作必要的增删：
“I got up early Monday morning. Mom told me that there was always heavy traffic, and as our car was a bit old and couldn't run fast, we'd better start earlier.”
18.2B 对缺乏一致性句子的两种处理方法
1） 为了取得句子的一致性，对句中与中心思想无关的内容应加删减。例如：
Parking space on the compass, which is one of the most beautiful in the state, has become completely inadequate, and recently the city council voted to increase bus fares again.
此句的中心内容是讲停车场已经非常紧张，市府决定再次提高公共汽车费，势必使更多的人用私人汽车，从而加剧停车场紧张的局面。由于which引导的从句同本句中心内容无关，故应删去。
2） 对于结构过于松散，未能明白地表示中心思想的句子应加以改写。例如：
I worry about whether I will get a job, and I am convinced that new opportunities will open up before the end of spring.
上例中的两个分句由逗号and连接，形式上是一个完整的句子，但实际上两个分句之间并未形成有机的连接，中心思想未得到明确的表述，为此应当改写。一种办法是把并列分句改为主从分句：
I worry about whether I will get a job, though I am convinced that new opportunities will open up before the end of spring.
也可以再增加一个分句，从而使全句的中心思想明白地表现出来：
I worry about whether I will get a job. Although I am convinced that new opportunities will open up before the end of spring, I still can't help being anxious about my prospects.
18.3 句子的连贯 （Sentence Coherence）
18.3A 句子连贯的含义
1） 句子连贯指句中的成分之间具有合乎逻辑的有机联系，全句所表述的思路清晰，使交际对方容易得到要领。例如：
It goes without saying that one cannot work logically with a statement which does not have a clear-cut, ascertainable meaning.
（John C. Sherwood）
这是一个以“it”作形式主语的句子，后面“that”从句为实际主语，在该从句中又以“not ... not”结构为主干，既紧凑，又清晰，确是一个有机整体。
2） 上节讲到的句子“一致”是指句中的成分都要围绕和服务于全句中心思想的表达，即与中心思想形成有机联系；这里讲到的“连贯”则是指句中的成分之间要形成有机的横向联系。“一致”和“连贯”，两者之间既有区别，又密切相关。例如：
All the players jumped from the bench and the referee made an unfair announcement of the results.
这是一个并列句，其两个分句之间表面上虽有and连接，但并未能表示出两个分句之间的逻辑联系，即未达到连贯要求，因而也未能实现句子的一致，结果整句的思想表达得不清楚。为此，应照下述方法加以改写：
The referee made an unfair announcement of the results and （so） all the players jumped from the bench.
As / When the referee made an unfair announcement of the results, all the players jumped from the bench.
All the players jumped from the bench because the referee made an unfair announcement of the results.
18.3B 影响句子连贯的若干因素
1） 从语法方面看，经常会影响到句子连贯的因素有并列结构安排失当，代词所指对象不明确，垂悬修饰或修饰语错位，时态、人称、数或语气不一致，句子结构混乱或不完全，等等。例如：
The report is chiefly about inflationary trends in the last decade and that the consumer has lost confidence in the quality of many products.
介词about的并列宾语一为短语，一为从句，属于并列结构安排失当，应当将that从句改为短语：
The report is chiefly about inflationary trends in the last decade and the consumer's loss of confidence in the quality of many products.
（James M. McCrimmon）
He rode that snowy night and slipped into a ditch, but it was not serious.
例中代词it所指不明确，故句子应加改写：
..., but luckily enough, he didn't get hurt.
又如：
Every member of our research team worked conscientiously, thus producing one of the best projects Professor Ames has ever received.
例中 -ing分词短语的修饰对象不明确，全句含义未能得到确切表达，故宜改为：
Because/As every member of our research team worked conscientiously, we produced one of the best projects Professor Ames has ever received.
又如：
Look at that ridiculous lady's hat!
修饰语位置不当会引起歧义或显得滑稽可笑，有时会造成误解。上例中的修饰语位置不当，应改为：
Look at that lady's ridiculous hat!
又如：
When we began our composition course, there was little knowledge about the importance of strategy in the writing of a paper. Correctness in spelling, punctuation, and grammatical usage was what had been drilled into us; but the effects of interrelationships among speaker, audience, and occasion were foreign to us ...
上例两个较长的句子讲的是作者，但由于用了4个不同的主语，影响了句子的连贯和一致，故应改为：
At the beginning of our composition course, we knew little about the importance of strategy in the writing of a paper. We knew the necessity for correctness in spelling, punctuation and grammatical usage but were unaware of the effects of interrelationships among speaker, audience, and occasion ...
2） 从修辞角度看，词语选用不当，辞格应用不当，重复、省略等其他修辞手法运用不当，都会影响到句子的连贯（同时也会损坏句子的一致）。例如：
On hearing that his father had kicked the bucket, I wrote him a letter to express my sorrows and sympathies.
句中“kick the bucket”是俚语，既粗俗，又轻浮，相当汉语中讲某人“翘辫子”。这里把俚语用到一个表示忧伤和同情的句子里，显然很不恰当，而应选用委婉语的形式，如“pass away”，“be no more”，“depart”，等。又如：
Flattens hills like flattens the floor.
这是一个广告稿，意在用夸张手法宣传使用该汽车爬山时高山变成了平地，但flattens重复使用时出现了败笔：既然是floor，就用不着再去flatten，为此应改为：
Flattens hills like driving on the floor.
又如：
The campaign was successful and costly, but the victory was sweet.
两个问题影响了句子的连贯：一是不应当用and连接两个含义上矛盾的并列成分，而应用表示转折、对照关系的but；二是用词不精练，successful和victory在含义上重复。该句可改写为：
The campaign was costly, but the victory was sweet.
18.4 句子的强调 （Sentence Emphasis）
18.4A 句子强调的含义
1） 句子的强调指把句中表示重要意义的成份或词语安排在句中较为显著的位置。一般说来，句首和句尾都是受强调的位置。请看下面两个例句：
Her hands were always moving, pushing her glasses back up her slim nose, patting her hair into place, tapping a non-existent ash off the end of her cigarette.
When my father had been wheeled into the recovery room, and the heart monitor and the glucose tubes had been disconnected, I finally relaxed.
（Francis L. Fennell）
上述例1为渐进句（参见7.3A），例2为掉尾句（参见7.2A），分别强调句首和句尾部分。
2） 对内容加以夸张，对某些词语加下横线，改粗体或斜体，以及使用感叹号，等等，都能起到强调作用。但这里所讲的强调主要指对句子结构的安排和调整，使作者想着重表达的思想得到突出，做到次要内容服务于主要内容，有轻有重，层次分明。
18.4B 句子强调的几种手段
1） 除上面18.4A2提到的以外，还可通过调整句中成分的位置的方式强调某个句子成份。例如：
The American girl drove her red car to school last semester.
若要强调句中的女孩是美国人，则可作如下调整：
The girl, an American, drove her red car to school last semester.
或
The girl, who was an American, drove her red car to school ...
又如：
She might never see him again if the plane came late.
若把条件状语从句提前，或者在主句与从句之间加上破折号，都可使原句的意思得到强调：
If the plane came late, she might never see him again.
或：
She might never see him again — if the plane came late.
2） 重复（参见7.4B）、省略（参见7.4A） 和平行对照结构 （参见16.3） 的使用，都是达到句子强调的有效方式。例如：
And this hell was, simply, that he had never in his life owned anything — not his wife, nor his house, nor his child — which could not, at any instant, be taken from him by the power of white people.
（James Baldwin）
We always called her old Maggie although she wasn't old really. About forty-seven, or forty-eight. No more.
又如：
Now is the time to rise from the dark and desolate valley of segregation to the sunlit path of racial justice, ... Now is the time to lift our nation from the quick sands of racial injustice to the solid rock of brotherhood.
（Martin Luther King Jr.）
练习十八 （Exercise Eighteen）
I. Preview Questions:
1. Can you tell the difference between Correct Sentence and Effective Sentence?
2. “Unity means oneness, the combination of all elements to form a single unit.” What do you think of this statement?
3. What should be done when a sentence lacks unity?
4. Is it true that sentence coherence requires that all elements be arranged in a clear, logical order so that it is easy for the reader to follow the writer's train of thought?
5. Can you tell any factor in grammar that will affect sentence coherence?
6. Can you tell any rhetorical factor that will affect sentence coherence?
7. What positions in the sentence are regarded as most prominent?
8. Can you indicate with an example how emphasis can be achieved in the sentence?
II. Read and comment the following statements:
1. For a sentence that lacks unity, there are three possible remedies: a） Delete any phrase or clause that is unrelated to the central thought; b） Subordinate one statement to another to show the logical relationship; and c） Separate seemingly disconnected statements, making two sentences, and bring in material that will provide a logical link between them.
2. Coherence is an essential virtue in expository writing, in which everything is tied together clearly and logically so as to help your reader to follow your ideas. These four points are necessary to achieve coherence: a） Use some logical method of organization; b） Structure your sentences in such a way that the sequence in which they are arranged links them to each other; c） Use transitional devices to connect sentences and paragraphs; and d） Repeat a key word or phrase to remind your reader of the important points of your essay.
3. Emphasis is used to indicate the relative importance of the points you are making, so that your reader recognizes the most important as most important, the less important as less important, the incidental as incidental. A lack of emphasis means a failure in guidance; misplaced emphasis means serious confusion. There are various devices to achieve appropriate emphasis, which include a） Proportion — Give the point you want to emphasize the space and development its importance calls for; b） Position — Generally speaking, the most emphatic position in a sentence, a paragraph, or a full essay is the end （hence the danger of leaving the final point undeveloped）, and the second most important is the beginning, therefore any negligence of these two positions should be avoided; c） Separation — Use a comma, a colon, or a dash to set off part of a sentence and thereby emphasize it, lightly or heavily, or begin a separate sentence or a new paragraph to achieve the same purpose; d） Repetition — Appropriate repetition of certain significant words or ideas in different wording, or perhaps in figurative expressions, can gain emphasis; e） Economy — Pay special attention to the expression of the ideas that deserve major emphasis, while stripping the sentences of any verbiage that blurs their clarity and blunts their impact; f） Mechanical devices — Using underlinings, capitals, and exclamation marks for emphasis is necessary from time to time, though various other devices can be used instead, i. e.“It is interesting to note”，“It's John that has been chosen”，“What I'd advise you is ...”, etc.
III. Try and revise the following, wherever you find necessary:
1. For almost ten weeks in January, the coldest month in that area and much colder than many of their home towns, the POWs were kept in an unheated camp at night, the cold caused many deaths and diseases and in particular, the victims were women and children.
2. Such plants to operate successfully had to run at capacity. As they wanted to do this, they needed outlets for their output.
3. Raghaven N. Lyer, writing in The Center Magazine, states that, “There are two kinds of infuriating people. One is the moralist, the other is the legalist. The moralists are infuriating when they want to raise every single issue, however local and specific, to the status of eternal principle; the legalists are infuriating when they want to reduce an important matter of moral principle involving basic human rights and human dignity to mere formalism or sheer expediency.”
4. Coherence means sticking together. A paragraph is coherent and the sentences are woven together or flow into each other. The reader then moves easily from one sentence to the next and reads the paragraph as an integrated unit, which is not a collection of separate sentences.
5. College is very different from high school. The professors talk a great deal more and give longer homework assignments. This interferes with your social life. It may even cost you a girlfriend. Girls don't like to be told that you have to stay home to study when they want to go to a show or dancing. So they find some other boy who doesn't have to study all the time. Another way in which college is different is the examinations. ...
