阅读理解之准确找出主鞑民略锈题句
阅读理解的技巧中非常重要的一点是在阅读中迅速地抓住文章或段落的中心思想。
段落的构成有其内在的规律，其中心思橇秆苡螳想往往是通过段落中的主题句来体现的。因此了解并掌握这些规律，迅速找出主题句，从而抓住中心思想对于提高阅读理解能力大有益处。
这些规律主要是通过主题句在段落中所处的不同的位置体现的。因此同学们首先应对以下四种段型有所了解，然后通过一系列有意识的训练掌握它们。
1．首句是主题句的规律
①给予例证、解释或说明的段落；
②下定义的段落；
③对两个或两个以上的事物作比较或对比的段落；
④表明原因和结果(往往结果交代在前)的段落。
主题句是首句的段落总是用演绎法撰写，遵循从一般到个别或特殊的写作程序，即以概述开段，随之辅以细说。这样的段落在文章中出现得最多，据专门研究阅读理论与技巧的专家们统计，概率达到70%。请看下例：
People who talk and sing toplants have no mental problems at all, according to an agricultural expert."In fact, singing and talking to plants makes them grow better," saysDr Braymar. The reason is quite simple. When we sing or talk to plants, weexhale(呼出) CO2which plants need to survive(continue to live)and grow better. Plants absorb (take in) CO2through their pores(小孔) during the sunlight hours and produce oxygen whichpeople to survive. Singing and talking have good effect on plants, however,only during the daytime. Singing or talking at bedtime will not help plants togrow better or grow faster.
本段的首句是主题句，其后的句子或是解释说明“对植物说话或唱歌有益于植物”，或是为这一主题思想提供论据。本段的结尾句呼应主题句，在给予主题思想又一论据的同时，幽默地收尾。
2．段落尾句是主题句的规律
(1)阐述一个不常见的或难以令人接受的观点的段落。
(2)旨在说服读者相信甚至信服其论点的段落。
尾句是主题句的段落总是用归纳法撰写的，其程序是先表述细节或交代论据，最后作出概括性的结论，以总结性的句子收尾。这种写作方法的特点是从个别到一般，由特殊性到共性。请看下例：
If you hadn't known them, youwould have thought Joe and Jim were quite alike. They were both tall and worelong and fair hair. They both walked with a steady stride (坚定的步伐). They both spoke in a deep voice that made themselves seem much older than they really were. Both of them wore dark clothes asa rule, and they liked light coloured ties. But that was all the likeness theyhad. In other things they were sharply different. Joe was considerate andhelpful, and everyone liked him. Jim, however, was very selfish and oftenflared into terrible anger (勃然大怒) at little things that displeased him. Alike as Joeand Jim were on the surface, they were really very different in nature.
这段文字从乔与吉姆两个人相像和不同的细节叙述，最后一句作了归纳总结：这两人表面相似，但实质极不相同。
3．段落中间句是主题句的规律
表述某种观点的段落的主题句往往处于段落的中间。这样段落先以一句或几句为主题句的出现作铺垫，或是交代一个细节或论据。在主题句出场后，仍有适当数量的句子陈述细节或继续给予例证。这类段落包括几个层次：引题—主题思想—解释或“提问”—回答问题或继续给予例证。这样段落的撰写总是遵循这条规律：先归纳后演绎。给出一两个例证之后，作出概括性的总结，然后根据这一结论再给予例证来证实其论点。请看下例：
When you throw a ball up intothe air as fast as you can, the ball reaches a point where it seems to pausefor a moment, and then it comes down. When a bullet (子弹) is shot straight up, it will travel much fasterand higher than a ball, but it, too, will come down.Whatever goes up mustcome down.We have al-ways thought this to be true. An airplane may climbto a height of seventeen miles and then travel far and long. Yet it does notstay up forever. Finally, like every-thing else, the plane must come down.
本段文字中间划线的这句话是主题句。其行文顺序与写作方法与上述的发展程序完全吻合。
