说到比较结构，今天石家庄朗欧教育讲师和福宝们来一起谈谈同一事物不同发展阶段的比较型文章，以及这类文章的出题要点。
唯美可爱烟花动图分割线
首先既然涉及到不同时期事物不同发展阶段的特点，必然就会比较阶段性的异同点，尤其是不同点的比较应该是我们关注的重点，所以我们要在听音过程中注意听明白不同发展阶段各自有哪些特点。
以TPO16 Lecture4第4题为例：
According to the professor, what are two ways in which stained glass windows made in the sixteenth century differed from those made in earlier centuries? Click on 2 answers.
A. The way the glass was colored.
B. The role played by lead strips.
C. The scenes that were depicted.
D. The way glass pieces were cut.
这道题目，相对难度是比较大的，因为文中信息相对分散，且答题点对精听的要求相对较高，所以这道题目在班级练习时错误率比较高。
文中以学生的提问：
And the lead strips that was just to hold the whole piece glass together?
引出了出题点，在这里出题点还是相对比较明显的，学生问lead strips的功能是什么，在之前的系列文中提到过一旦听力原文中出现新名词我们需要努力听懂这个词的定义解释和功能作用，因为这往往是出题点或者是理解上下文的关键信息，原文中教授的回答是：
Well, uh, lead strips is strong and flexible so it’s ideal for joining pieces of glass cut in different shapes and sizes. Uh, but up to the 15th century, the lead strips also helped created the design. They were worked into the window as part of the composition. Uh, they were used to outline figures to show boundaries, just like you might use solid line in a pencil drawing.
教授介绍lead strips的特点是非常棒的粘合材料，并且告诉学生在15世纪lead strips是设计的一部分，就好像铅笔画的实心线一样勾勒出形象的边界。
然后接着学生提问关于上色的问题，这里出题点是相对简单也比较容易掌握的：
How did they get the color? I mean, how did they color the glass?
教授的回答是：
Well, up until the 16th century, stained-glass was colored during the glass making process itself. Uh, you got specific colors by adding metallic compounds to the other glass-making ingredients. So, uh, if you wanted red, you added copper. If you wanted green, you added iron. You just added these compounds to the other ingredients that the glass was made of.
即16世纪前人们是利用在玻璃制造过程中加金属元素来使玻璃染色。这样的制作工艺每片玻璃只有一种颜色。
16世纪之后人们采用了另一种给染色玻璃上色的方式：
Yes, at least up until the 16th century. Uh, then they started, uh, you started to get painted-glass. Painted-glass windows are still referred to as stained-glass, but the colors were, actually, painted directly onto clear glass after the glass was made. So, um, with this kind of stained-glass, you could, uh, paint a piece of glass with more than one color.
即通过给透明玻璃涂色的方式来制作彩色玻璃片，在文中以16世纪作为一个时间分割点，前后给玻璃上色的方式不同，这点相对来讲是比较容易理解的。
这个不同点对应题目中的选项A：
The way the glass was colored.
而相对来说比较难的是另一个选项，这个点在文章中的出题点也是相当明确的，学生再次提问说：
And with painted-glass they still used the lead strips?
也就是说16世纪之后一大片玻璃已经可以有很多种不同的颜色了，人们还需要使用lead strips吗？教授的回答是肯定的：
Yes, with really large windows it took more than one piece of glass, so you still needed lead strips to hold the pieces together. But the painters actually tried to hide them, so it was different from before when the lead strips were part of the design and it’s different because with painted-glass the idea of light coming through to create the, uh, magical effect wasn’t the focus anymore. The paint work was, and painted-glass windows became very popular.
因为对于很多非常大的玻璃窗还是需要lead strips来起到粘合作用，但是此时绘画者会刻意的去隐藏他们，因为在这个时期lead strips不再是设计的一部分，人们不再追求光线穿透的魔法效果，而是更注重绘画本身。
这里有一个非常关键的出题信号词，就是学生的提问，因为学生已经是第二次就lead strips提问，其次在教授的回答中教授用了一个转折词but，一个强调词actually，一个表示比较不同点的表达it was different from before。
所以以上这些信息都提醒我们这里是重要的出题点，对应到第四题中的选项B：
The role played by lead strips.
通过这道例题，希望福宝们能够理解，在托福听力文章中，一些讲述发展史的文章，纵向要注意每个发展阶段的特点，同时也要注意每个阶段发展阶段的不同点，以TPO9lecture3的第四题为例：
How is it possible to determine in which rainy period a lake was formed? Click on 2 answers.
A. By examining the location of the lake bed.
B. By measuring the amount of sand covering the lake bed.
C. By examining the color of the limestone formation.
D. By identifying the types of fossils found in the limestone.
文章开头部分就有提到：
There were actually two periods of rain and lake formation: the first one began about 37,000 years ago; and the second one dates from about 10,000 years ago.
从时间上将沙漠当中的湖分成了两种类型。
后续文中有提到：
Another difference, very important today for distinguishing between older lake beds and newer ones, is the location of the limestone formations.
这里出题点提示性很强，用到了Another difference，very important，distinguishing等表示差异和强调的词来引起同学们对于信息点的重视，所以这个部分对应题中选项A：
By examining the location of the lake bed.
后续文中又用一个转折引出了另一个不同点：
At older lake sites, there’s fossil remains from hippopotamuses, water buffalo, animals that spend much of their lives standing in water, and also, fossils of cattle. However, at the sites of the more recent lakes, there’s only cattle fossils, additional evidence for geologists that these lakes were probably smaller, shallower, because cattle only use water for drinking. So they survive on much less.
即不同时期湖中的化石不同，对应选项D：
By identifying the types of fossils found in the limestone.
希望通过这两道例题，能够让福宝们们在遇到类似篇章和题目的时候有更加敏锐的预测出题点的能力，提高做题的正确率~当然在这里也告诉大家一个好消息，石家庄朗欧教育暑假班课即将开始，想要暑期学习的学子们赶紧行动起来吧。
