刚刚接触托福阅读时，同学们看到几个数字就会倒抽一口凉气：700字，14道题，20分钟。而如果希望托福阅读达到25分以上，老师建议大家先浏览每段的主题句，这种方法毫无疑问就像一剂强心针，安抚了同学们的兵荒马乱。但是与此同时，另一个问题又产生了——只见树木不见森林。托福阅读真是一道题对应一个段落，那么其他段落的内容就完全身处世外吗?
我们先来看一个例子：
Q: Paragraph 2 suggests which of the following about the importance of population density in the industrialization of the Netherlands and Scandinavia?
A. It was a more important factor than population size.
B. It was more influential than the rate of population growth.
C. It was more important in the early stages than it was later.
D. It was not a significant factor.
Paragraph 2: All had small populations. At the beginning of the nineteenth century, Denmark and Norway had fewer than 1 million people, while Sweden and the Netherlands had fewer than 2.5 million inhabitants. All exhibited moderate growth rates in the course of the century (Denmark the highest and Sweden the lowest), but all more than doubled in population by 1900. Density varied greatly. The Netherlands had one of the highest population densities in Europe, whereas Norway and Sweden had the lowest Denmark was in between but closer to the Netherlands.
这是来自TPO18里的一道推断题，一般做题思路是先找定位词，然后文本分析，最后选择答案。这道题定位之后会找到最后两句话都跟density有关系，但是要想从这两句话把答案
找到，这未免太强人所难。而如果在做题之前，大家对这篇文章的主题以及布局有一个大致的了解就会容易得多。
在托福文章里一般每个段落的第一句话就是这个段落的主旨句，所以只要读完每段的第一句，再进行稍微的梳理，这篇文章的大意也就比较清楚了。上面提到的这篇文章总共6段，每段的主题句分别如下：
1)While some European countries, such as England and Germany, began to industrialize in the eighteenth century, the Netherlands and the Scandinavian countries of Denmark, Norway, and Sweden developed later.
2)All had small populations.
3)Considering human capital as a characteristic of the population, however, all four countries were advantaged by the large percentages of their populations who could read and write.
4)Location was an important factor for all four countries.
5)The political institutions of the four countries posed no significant barriers to industrialization or economic growth.
6)The key factor in the success of these countries (along with high literacy, which contributed to it) was their ability to adapt to the international division of labor determined by the early industrializers and to stake out areas of specialization in international markets for which they were especially well suited.
整理之后，我们不难发现这篇文章就是在讲荷兰和斯堪的纳维亚国家的工业进程及其发展的原因。其中用两段来探讨了“人”的重要性——虽然人数不多，但是人口素质较高促进了工业化的进程。掌握了这一条线索，那上面的那道题也就迎刃而解：density无足轻重，答案选D。
