第二节 段落的基本结构

段落是文章的基本构成成分，其作用是围绕文章的主题或中心思想从不同角度进行有组织的、逻辑性强的说明或阐述。段落由一系列围绕同一主题的句子组成。当新的主题出现时，就应开始新的段落。段落一般由三部分构成：主题句（topic sentence）、支撑句（supporting sentence）或扩展句（developing sentence）和结尾句（concluding sentence）。请看下面的一篇短文：
What is a topic sentence?
The topic sentence introduces the paragraph.
What does it do?
It tells the reader what your paragraph will be about.
Example:
There are three reasons why I want to learn English. One reason is that English has become an international language. It is now used by most international companies, including the company where I work, for business communication. Another reason why I want to learn English is so that I can travel to English-speaking countries. The United States, England, Australia and many other countries all use English as their primary language. Finally, I want to learn English because I plan to move to the U.S. in the future. I will become a manager for my company soon. For all these reasons, I am very excited about learning English.
ANALYSIS:
What are you going to tell the reader about?
Topic Sentence: There are three reasons why I want to learn English.
文章中的第一句就是段落的主题句，顾名思义，段落的主题句是表达该段落主题或中心思想的句子，段落的其他句子都是对该主题句的进一步扩展或论证。所以，写好主题句往往是写好文章的关键。在构思主题句时，应注意两个常见的问题，一是主题句太空泛，没有具体内容；二是因一个段落中出现一个以上的主题句而使得段落的中心内容不明确。段落的主题句一般位于段落的开头，尤其是对议论文更是如此。
同样是这篇文章，我们再来看一下它的支撑句。
Supporting Sentences
What are supporting sentences?
supporting sentences come after the topic sentence, to explain your topic sentence.
The supporting sentences with their supporting details make up the body of a paragraph.
What do supporting sentences do?
They give information to develop and support the main idea of the paragraph.
How do I write supporting sentences?
You should give information, facts, details, and examples.
supporting sentences often answer the question "Why?"
Example:
There are three reasons why I want to learn English. One reason is that English has become an international language. It is now used by most international companies, including the company where I work, for business communication. Another reason why I want to learn English is so that I can travel to English-speaking countries. The United States, England, Australia and many other countries all use English as their primary language. Finally, I want to learn English because I plan to move to the U.S. in the future. I will become a manager for my company soon. For those reasons, I want to learn English.
ANALYSIS:
Why do you want to learn English?
Main point: because English has become an international language
一篇文章的主体，除了要有支撑句外，还需一些细节（details）的支撑。
What are details?
Details come after the main points, to explain your point, or give extra information about the main point. The details fill out the body of a paragraph and make it more clear.
What do details do?
They give extra information to support your main points.
How do I write details?
You should give details, and examples. Details often answer the question "How?"
Example:
There are three reasons why I want to learn English. One reason is that English has become an international language. It is now used by most international companies, including the company where I work, for business communication. Another reason why I want to learn English is so that I can travel to English-speaking countries. The United States, England, Australia and many other countries all use English as their primary language. Finally, I want to learn English because I plan to move to the U.S. in the future. I will become a manager for my company soon. For those reasons, I want to learn English.
ANALYSIS:
Main point: English has become an international language
 Detail: It is now used by most international companies
 Detail: It is used by the company I work for
Main point:  I want to travel to English-speaking countries
Detail: The United States uses English as the primary language.
Detail: England uses English as the primary language.
Detail: Australia uses English as the primary language.
Detail: many other countries use English as the primary language.
Main point: I plan to move to the U.S. in the future
Detail: I will become a manager for my company
一篇文章要有始有终，到了文章的结束部分，往往会出现结尾句。
Closing Sentence (Conclusion)
What is the closing sentence?
The closing sentence is the last sentence in a paragraph.
What does it do?
It restates the main idea of your paragraph. It tells the reader what you were writing about.
How do I write a closing sentence?
Restate the main idea of the paragraph using different words.
Example:
There are three reasons why I want to learn English. One reason is that English has become an international language. It is now used by most international companies, including the company where I work, for business communication. Another reason why I want to learn English is so that I can travel to English-speaking countries. The United States, England, Australia and many other countries all use English as their primary language. Finally, I want to learn English because I plan to move to the U.S. in the future. I will become a manager for my company soon. For all these reasons, I am very excited about learning English.
ANALYSIS:
What did you tell the reader about?
Closing Sentence: For all these reasons, I am very excited about learning English.
Conclusion
This is your last sentence, therefore the most important. This will be the sentence that is most fresh in the readers' mind after they put the paragraph down. A good way to form your conclusion is to reform the introductory paragraph in reverse form. In other words, have the conclusion contain the following, in the order written:
Restate your topic sentence, but in different words than before.
Close with a general statement that reflects insight on your topic.
结尾句不是主题句的简单重复，而是对它的扩展与总结。

课堂练习
1．找出下列段落中的主题句。
Lying in Bed
Lying in bed can be dangerous to your health. Once people believed that staying in bed was best cure for illnesses or injuries, but doctors who have studied the effects of bed rest are rewriting the medical textbooks. The harmful effects of bed rest were first noticed during World War II. Some field hospitals were not equipped to give much nursing care to the wounded soldiers. As soon as possible after surgery, the nurses stopped bathing them ad bringing them their meals. The results were surprising: the soldiers getting less care recovered sooner and better than those elsewhere who were permitted to remain lying in bed without stirring.

Books
Perhaps the highest use of books is not as sources of information abut nations, people, or foreign lands, but as friends. Reading is one of the most effective means of getting away from disturbing, and unalterable circumstances. Intimate association with noble works, whether literary, philosophic, or artistic, is a promoter of thought, a refuge from almost all the miseries of life.

Walking
   I take a walk every day. Walking makes me feel better because it strengthens my muscles and gives me a good appetite. Walking also relaxes my mind, because it is rhythmical and noiseless, and requires no conscious thought. Walking is, for me, excellent physical and mental relaxation and exercise.

2．分析判断下列段落
A University Professor
1A university professor has many duties. 2In the classroom, he or she lectures to the students and answers questions. 3If the professor is a science instructor, he or she also conducts laboratory experiments. 4During office hours, students are free to visit the professor to get help on difficult material or problems. 5In addition, a professor may often work for many hours in laboratory doing a research project. 6Another professor might spend his or her time writing a scholarly paper for a professional journal. 7Still another one might spend time writing a book. 8In conclusion, a professor is always a very busy person.

第一句是__________________     
第二---七句是________________      
第八句是___________________