Q: What is the talk mainly about
A. A common method of managing water supply。
B. The formation of underground water systems。
C. Natural processes that renew water supplies。
D. Maintaining the purity of underground water system。
文章中的这句话 “I wanted to discuss a few other terms here…some ideas about”很明确的点出了文章的内容主旨。根据上面的讲解，我们很容易把握discuss和about这两个词!所以，about后面的“how we manage our resources”就是文章的主旨了!所以根据同义替换，我们可以将“how”这个词替换为A选项的method而且of 后面的宾语(managing water supply)也同原文内容(how we manage our resources)一致!正确答案为A.。
2). 以how, what, why开头
e.g. Script
…so the Earth’s surface is made up of these huge segments, these tectonic plates. And these plates move, right But how can, uh, motion of plates, do you think, influence climate on the Earth Again, all of you probably read this section in the book, I hope, but, uh, uh, how— how can just motion of the plates impact the climate
Q: What is the main topic of the talk
A. The differences in climate that occur in different countries。
B. How movement of the Earth’s plates can affect climate。
C. Why the ocean has less effect on climate than previously thought。
D. The history of the climate of the region where the college is located
这道题可以明显根据部分文章重复找出答案!重复句式为“But how can, uh, motion of plates, do you think, influence climate on the Earth”去掉其中的插入语，我们可以提炼出“how can motion of plates influence climate on the Earth”。与这句话一致的是B选项!其中，可以找到原文与选项的同义替换是motion=movement、effect= impact/ influence。从这道题目可以看出：特殊疑问词也是主旨题正确选项的一大特征!
3) To do
e.g. Script (lecture)
Ok. Another ancient Greek philosopher we need to discuss is Aristotle– Aristotle’s ethical theory. What Aristotle’s theory is all about is this: he is trying to show you how to be happy—what true happiness is。
Q: What is the main purpose of the lecture
A. To illustrate the importance of extrinsic values
B. To explain Aristotle’s views about the importance of teaching
C. To explain why people change what they value
D. To discuss Aristotle’s views about human happiness
“To do”结构在主旨题中出镜率很高，目的主旨的选项大部分以to do结构开头。那么，解题的宗旨就是比较动词do的形式和用词!如果原文中用到的动词与选项一致，同学可以首先定位此选项，再比较后面的宾语即可。 “Ok. Another ancient Greek philosopher we need to discuss is Aristotle– Aristotle’s ethical theory。”从原文中可以看到discuss这个词，那么这个词正好与D选项中的discuss相吻合，而其后的宾语“human happiness”也一致!所以答案无可厚非为D。若选项中 “do”的形式与原文不一致，那么我们需要做的就是同义替换。请看下面的例子：
e.g. Script (conversation)
S: I was hoping you could look over my note cards for my presentation…just to see what you think of it。
P: Okay, so refresh my memory: what’s your presentation about
Q: Why does the student visit the professor
A. To get some note cards for his presentation
B. To show her some examples of common errors in research
C. To review the notes for his presentation with her
D. To ask for help in finding a topic for his presentation。
在这篇文章中，引导conversation主旨题的标志词是I was hoping， 在其之后出现的动词关键词是look over。名词关键词为：note cards for my presentation。所以，与原文一致的选项应该找look over的同义替换，即review!所以应该选择C选项。
以上就是主旨题需要注意的细节信息和解题技巧，希望能对大家在准备托福听力考试的过程中起到指引作用。
托福考试频道推荐阅读