写作中,先叙述事情发展的原因,再叙述结果,或先叙述结果,再解释原因,这种方法叫因果法。如:
Climate affects the culture of a country. Men must learn to live within the limitations of their environment, and environment is an im-portant part of the physical environment. Life in a tropical country is less strenuous and more casual than it is in a temperate one. Men work shorter hours and less vigorously in a hot climate. They cannot play hard either. They tire easily. They can relax by reading, by sipping cool drinks, or by listening to soothing music. They must try to conserve their energy. The wisest ones learn to respect the demands on Nature.
此段第一句为主题句,先点明原因:“气候影响一个国家的文化”,其余各句则分别说明由此所造成的后果。
Three causes led to my failure in the exam. First, I did not work hard to prepare for it. Second, I was always nervous when taking the exam. Third, I was very careless when I was answering the questions.
此段第一句为主题句,先交代结果:“我未通过考试”。其余各句则具体说明了导致这一后果的原因。
7.分类法
分类法是根据事物的性质、形态、原因或功能等特征进行分类,然后就各类分别加以叙述。根据文体将文章分成记叙文、描写文、说明文、议论文等文体。如:
All matter is one of the three states.It maybe in the state of a gas,a liquid or a solid.A solid has definite shape and definite volume.A liquid has definite volume,but it has no definite shape.It may flow or take the shape of its container.A gas changes not only in shape but also in vol-ume,for it expands and contracts easily.
该段首句为主题句,介绍了一切物质都处于三种状态中的一种状态下。其余的句子分别说明了事物处于三种状态下的特征。
分类时要注意确保界线清楚,不能交叉重叠。同时要注意使被分的每一事物都应属于其中的某一类。而且在主题句中应写明根据什么原则以及把这些事物分成多少类或哪几类,然后逐类加以分析说明。比如我们可将苹果按大小分成大苹果和小苹果,按颜色可分成红色和绿色。若将苹果分成大苹果和红苹果则不合理。因为大苹果很可能也有红色的,界线就不分明了。
8.定义法
写作时要对读者不熟悉或有多种解释的单词、术语、概念,一件事物(或人)下定义并根据定义来叙述该事物或概念的细节或特征等。这种写作方法叫定义法。用定义法发展段落时,段落的主题句就是定义句,概述被定义事物的种属及种差,扩展句部分展开叙述有关方面的内容,如被定义物的来历、性质、特征等。如:
A pencil is an implement for writing,drawing,or marking.The usual pencils have three parts:a wood case,a solid rod of graphite,and a small eraser.The wood cases of most pencils are round.Inside the wood case,there is a solid rod of marking material,which gives the pencil its special writing characteristic.At the end of the wood part,there is a small colored eraser for removing the unwanted writings.The eraser is fixed to the main part by a small,round piece of metal.Although the colors of the wood case and the writing material inside it differ from one pencil to another,the usual length and weight are 25cm and 10g.The shape allows the pencils to fit easily in the hand when it is correctly held between the thumb and the index and middle fingers,and in the pocket when it is carried.
该段的首句为定义句,阐明了pencil的种属an implement,及种差for writing,drawing,or marking。其余句子分点介绍了铅笔的构成部分及用途等有关细节。
9.列举法
列举法是一种常见的发展段落的方法。用这种方法发展段落,作者首先摆出一个论点,然后列举一系列论据对其进行陈述或解释。列举的顺序可根据各点内容的相对重要性,时间的先后或地理位置的远近关系来进行。如:
What are some of the advantages of shopping and eating under-ground?Clean,fitered air is one of them.The city of Tokyo has one of the most serious smog problems in the world.Another advantage is that you escape the everpresent threat of traffic accidents on the city's busy streets.Still another is the convenience of getting around.You are usually right next to,or even in,a subway station.
该段第一句为主题句,扩展句部分按照重要性递减的顺序列举了三个优点来说明主题句。
以上介绍了几种常用的发展段落的方法。实际写作时,一个段落并不只是使用一种发展方法,有时一个段落可以使用多种写作方法,例如用举例法可以结合时间顺序法发展段落,我们可以用读者熟悉的事物来解释对他们来说是陌生的东西,因此,定义法常和比较——对比、举例等方法结合使用。
