4．1段落的推展
在前几单元中，我们谈到写段落的第一个步骤是写主题句。作者要对主题句在某些方面加以限制。第二个步骤将是写推展句。例如你要陈述你选择某院校的理由，第一步，写出主题句：
There are two main reasons why I have decided to attend Bingston University next year．
第二步，以数个理由推展你的主题：
示范段落4-1
① There are two main reasons why I have decided to attend Bingston University next year．② First of all， there is the question of money：Bingstonv's tuition is reasonable and I don't even have to pay it all at once．③ This is very important， since my father is not a rich man．④ With Bingston's "deferred payment plan，" my father will be able to pay my tuition without too much difficulty．⑤The second resaon is the fine education which I feed will receive there in agriculture， my chosen field．⑥ It is a well-known fact that Bingston hires only the finest professors in its Agriculture Department．⑦ Moreover， the university reqires all agricultural students to get practical experience by working on farms in the areawhile they are still going to school．
4．2示范段落分析
细节： two main reasons：
理由 1-financial consideration②
a． reasonable tuition③
b． deferred payment plan④
理由 2-quality of education⑤
a． fine teachers③
b． practical experience⑦
在两个主要理由之下，作者用更小的细节支持它们。
由此可见，段落的推展依赖于支持主题句的细节（details）。推展段落的方法很多。通常每个段落以一种方法为"支配方法"（ the dominant method），必要时，可运用其它一种或数种方法作为"辅助方法"（ the supporting method）。上面的示范段落使用因果法（cause-and-effect）作为支配方法，分类法（division and classification）作为辅助方法。作者还运用了"重要性排列顺序"（the order of importance）作为安排细节、组织段落的手段。我们将在以下各单元逐个讨论这些方法。
Exercise4-1
Directions： Read the following paragraphs and find out what details the authors use to support their topic sentences．
（1） Warm water freezes more quickly than cold． Sir Francis Bacon stated that almost four hundred years ago． But few people believedhim-till 1970． In that year， Canadian scientist George Kell proved the English scholar right． Dr． Kell filled an open pail with cold water． He filled another with warm water． He exposed both to the same low temperature． The warm water froze first．
Topic Sentence：____________________________________________
Details：1．________________________________________________
2．________________________________________________
（2） There is a relationship between your blood type and your nationality． Among Europeans and people of European ancestry，about 42 percent have type A while 45 percent have type O．The rarest is type B． Other races have different percentages．For example， some American Indian groups have nearly 100 percent type O．
Topic Sentence：____________________________________________
Details：1．________________________________________________
2．________________________________________________
（3） Although thousands of people have been killed by sudden eruptions， volcanoes also benefit man， Tin， tungsten， gold and other metals have been brought closer to the earth's surface．Chemicals in the ash have enriched farmland． When solid， lava is agood building material． And in Italy， steam from active volcanoes supplies heat and power to surrounding areas．
Topic Sentence：____________________________________________
Details：1．_______________________________________________
2．_______________________________________________
3．_______________________________________________
4．_______________________________________________
（4） The Women's Movement has had several effects on the English language． It has created Ms， a title for women comparable to the title Mr． for men． The creator of the new title objected to the title Miss and Mrs． once given to women because these titles violated a woman's privacy by indicating her marital status． The use of Ms．now permits women to enjoy the same privacy that men have enjoyed with the use of Mr． Second， the Movement has changed the ending of many compound words from-man to-person．For instance， the word "chairman" has been replaced in many organization with the word "chairperson"， and the word"salesman"has become salesperson． Feminists insist that the substitution of-person for-man makes the position more suitable for members of either sex． Third， the Movement is responsible for new terms．One example is male chauvinist pig， a term applied to a man who refuses to recognize the equality of women． Another example is female chauvinist sow， a phrase used to describe a female who believes that she is superior to males． The most profound effect the Movementhas had on the language is on the third person singular pronoun．Thirty years ago most English instructors forced their students to se he， him， and his for the third person singular when the sex of the person was not known． Thus， students were taught to say，"Everyone has his books"．Today many English teachers permit students to follow the feminist lead and use the masculine and feminine pronouns together． Therefore， constructions such as his or her books are common． Although the Women's Movement may not have yet achieved all of its goals， it has made a mark on the English language．
Topic Sentence：___________________________________________
Details：1．______________________________________________
2．______________________________________________
3．______________________________________________
4．______________________________________________



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