托福阅读修辞目的题是阅读考试中比较常见的一种题型，tpo则是托福阅读备考最权威的材料 ，所以托福小编综合二者，为大家集中整理了tpo阅读中考察的修辞目的题及其对应的解析，供大家参考使用。本文带来的是TPO6-2的修辞目的题，一起来看看吧。
TPO6-2 William Smith
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In 1831 when Smith was finally recognized by the Geological Society of London as the “father of English geology”, was not only for his maps but also for something even more important.Ever since people had begun to catalog the strata in particular outcrops, there had been the hope that these could somehow be used to calculate geological time.But as more and more accumulations of strata were cataloged in more and more places, it became clear that the sequences of rocks sometimes differed from region to region and that no rock type was ever going to become a reliable time marker throughout the world.Even without the problem of regional differences, rocks present a difficulty as unique time markers Quartz is quartz—a silicon ion surrounded by four oxygen ions—there’s no difference at all between two-million-year-old Pleistocene quartz and Cambrian quartz created over 500 million years ago.
7. Why does the author use the phrase “Quartz is quartz"?
○To describe how the differences between Pleistocene and Cambrian quartz reveal information about dating rocks
○To point out that the chemical composition of quartz makes it more difficult to date than other rocks
○To provide an example of how regional differences in rock sequences can make a particular rock difficult to date
○To explain that rocks are difficult to use for dating because their chemical compositions always remain the same over time
解析：先读所在句子，去调插入语后，插入语之后说两百万年前的quartz和五亿年前的quartz没有任何区别，往前看，前文说即使没有regional difference也不行，紧接着后面就说还有时间差异;所以答案是D
[3]1831年，史密斯最终被伦敦地质学会认可，并赋予他“英国地质学之父”的称号，这不仅仅是因为那张地图，而且是为了其他更重要的原因。从人们开始对露出地面的特殊岩层进行分类的时候起，大家就开始认为这些岩石可能会以某种方式被用于计算地质年代。但是，随着各地越来越多的岩层的积累和分类，岩层顺序也因地区的不同而不同，因此，全世界没有一种特定的岩层能被认作是划分地质年代的标志。即便排除区域差异的影响，岩石作为确定年代的标记还是存在一些难题。石英就是石英---四个氧离子包围一个硅离子的化合物——而200万年前更新世的石英和5亿年前寒世纪的石英并无差别。
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Not only could Smith identify rock strata by the fossils they contained, he could also see a pattern emerging：certain fossils always appear in more ancient sediments, while others begin to be seen as the strata become more recent. █ By following the fossils.Smith was able to put all the strata of England's earth into relative temporal sequence. █About the same time, Georges Cuvier made the same discovery while studying the rocks around Paris. █Soon it was realized that this principle of faunal(animal)succession was valid not only in England or France but virtually everywhere. █It was actually a principle of floral succession as well, because plants showed the same transformation through time as did fauna. Limestone may be found in the Cambrian or-300 million years later-in the Jurassic strata but a trilobite—the ubiquitous marine arthropod that had its birth in the Cambrian—will never be found in Jurassic strata, nor a dinosaur in the Cambrian.
12. In mentioning "trilobite”, the author is making which of the following points?
○Fossils cannot be found in more than one rock stratum.
○Faunal succession can help put rock layers in relative temporal sequence.
○Faunal succession cannot be applied to different strata composed of the same kind of rock.
○The presence of trilobite fossils makes it difficult to date a rock.
解析：先读trilobite所在句，说灰岩会在寒武纪或者侏罗纪出现，但特殊时代的生物只会在特定时间出现。也就是生物比岩石类型可靠，B正确;其他的都没说
[5]史密斯不仅可以通过岩石中包含的化石来识别地层，而且可以看出他们显露出来的模式：一些特定的化石往往出现在更为久远的沉积物当中，而其他的化石则可以在距今年代较近的地层中发现。通过追踪化石，史密斯将英国范围内所有的地层进行了彼此出现时间的排序。同时，乔治•居维叶在研究巴黎周围的岩石时也得出了同样的发现。很快人们就开始认识到，这种动物物种的延续性是符合逻辑的，不仅仅是在英国、法国，而实际上在全世界范围都是适用的。事实上，这一原则同样适用于证实植物的延续性，因为植物和动物一样，它们的化石也显示了时间的推移。人类有可能在侏罗纪时期的地层中发现寒世纪或者3亿年后的石灰岩，但绝不可能在侏罗纪时期地层中发现三叶虫化石(三叶虫是寒世纪非常普遍的水生节肢动物)，也不可能发现寒世纪时期的恐龙化石。
以上就是托福阅读TPO6-2中的修辞目的题及其解析，大家可以在备考的时候参考复习，希望能够帮助大家的考前准备。最后前程百利祝大家都能取得理想的托福考试成绩。
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