在第四单元，我们曾提到推展段落的方法有多种。从这一单元开始，我们将逐个介绍这些方法。
8．1事实与数据法
事实（a fact）是可以客观证实的事情。例如："The sunrises in the east．"是个事实。"Oil and water do not mix．"也是个事实。两者都可以通过实验证明是真实的。但是"Eating carrots improves eyesight．"也许是真实也许是不真实的。这不是个事实，是一种看法（opinion）。数据（a statistic）是一个数字事实（a numeral fact），用于给某一主题提供有意义的信息。例如：
There are twenty－five students in the class．"是一个数据。
示范段落8－1
The term population explosion is usually applied to the rapid growth of population over the last three centuries．In the two hundred years from 1650 to 1850，world population doubled and reached its first billion．In the next eighty years，it doubled again，and by 1975，it had doubled once more to a total of 4 billion．By the year 2000，it is estimated that it will exceed 6 billion and possibly approach 7 billion unless there is a major reduction in birth rates or amajor increase in death rates．
8．2示范段落分析
主题句：The term population explosion is usually applied to the rapid growth of population over the last three centuries．
提供信息：
数据1：1650-1850；double，reach 1 billion
数据2：1850－1930；double again，reach 2 billion
数据3：1930－1975；double again，reach 4 billion
数据4：1975－2000；exceed 6 billion，approach 7 billion
示范段落8-2
A snake is a strange animal．It walks on its ribs and it smells with its tongue．Since its teeth are sharp like needles and not good for chewing，it swallows its food whole．
8．3示范段落分析
主题句：A snake is a strange animal．
事实1：walks with its ribs and smells with its tongue
事实2：swallows its food whole
8．4关于如何写事实与数据段落的建议
1）不要把事实与看法混为一谈
事实是真实的，因为它们已被证据证实。然而看法只是人们的主观想法，不一定真实。因此，记住用事实而不是用看法支持你的观点。
2）不要使用不相关的数据
如果你为了增加观点的可信度而使用不相关的数据，即使这些数据是真实的，也会引起误解。
Exercise 8-1
Directions：Write a paragraph with statistics as supporting details，using the given topic sentence and statistics．
Statistic：blood pressure before the exam-115／55
Statistic：at the end of the exam-155／115
Statistic：ten minutes after the exam-150／110
Exams apparently have a marked effect on the blood pressure of the students taking them．___________________________________________________
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Exercise 8-2
Directions：Write a paragraph with facts as supporting details using the given topic sentence and facts．
Fact：William is the second most common boy's name used in English（the first being John）
Fact：History is full of Williams．
a．William of Nor many-conquerer of England in 1066
b．William Shakespeare-writer
c．William Cody-a hero of the Wild West
Is your name William？If so， you have company．____________
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