TPO是托福备考圣经，但是并不是有“圣经”就能完全把握托福考试。还要看大家怎么去利用这份资料。针对原文，我们可以最大限度的剖析再剖析。直到把文章掌握得滚瓜烂熟。而大家又是怎样对待其中的每个考题呢？是做完对对答案，记下答对率；还是认真分析每个考题在考什么，找出托福阅读的“点”在哪？前者居多吧！
所以，关于托福阅读TPO，托福小编希望最大限度地利用这些ETS提供的阅读题目。在题目中，找到每个题目考察点，给出最全最有逻辑的解析。今天，小编分享给大家的是关于TPO2 The Origins of Cetaceans的题目分析。
The Origins of Cetaceans
鲸类的起源
1.It should be obvious that cetaceans—whales, porpoises, and dolphins—are mammals. They breathe through lungs, not through gills, and give birth to live young. Their streamlined bodies, the absence of hind legs, and the presence of a fluke1 and blowhole2 cannot disguise their affinities with land dwelling mammals. However, unlike the cases of sea otters and pinnipeds (seals, sea lions, and walruses, whose limbs are functional both on land and at sea), it is not easy to envision what the first whales looked like. Extinct but already fully marine cetaceans are known from the fossil record. How was the gap between a walking mammal and a swimming whale bridged? Missing until recently were fossils clearly intermediate, or transitional, between land mammals and cetaceans.
2.Very exciting discoveries have finally allowed scientists to reconstruct the most likely origins of cetaceans. In 1979, a team looking for fossils in northern Pakistan found what proved to be the oldest fossil whale. The fossil was officially named Pakicetus in honor of the country where the discovery was made. Pakicetus was found embedded in rocks formed from river deposits that were 52 million years old. The river that formed these deposits was actually not far from an ancient ocean known as the Tethys Sea.
3.The fossil consists of a complete skull of an archaeocyte, an extinct group of ancestors of modern cetaceans. Although limited to a skull, the Pakicetus fossil provides precious details on the origins of cetaceans. The skull is cetacean-like but its jawbones lack the enlarged space that is filled with fat or oil and used for receiving underwater sound in modern whales. Pakicetus probably detected sound through the ear opening as in land mammals. The skull also lacks a blowhole, another cetacean adaptation for diving. Other features, however, show experts that Pakicetus is a transitional form between a group of extinct flesh-eating mammals, the mesonychids, and cetaceans. It has been suggested that Pakicetus fed on fish in shallow water and was not yet adapted for life in the open ocean. It probably bred and gave birth on land.
4.Another major discovery was made in Egypt in 1989. Several skeletons of another early whale, Basilosaurus, were found in sediments left by the Tethys Sea and now exposed in the Sahara desert. This whale lived around 40 million years ago, 12 million years after Pakicetus. Many incomplete skeletons were found but they included, for the first time in an archaeocyte, a complete hind leg that features a foot with three tiny toes. Such legs would have been far too small to have supported the 50-foot-long Basilosaurus on land. Basilosaurus was undoubtedly a fully marine whale with possibly nonfunctional, or vestigial, hind legs.
5.An even more exciting find was reported in 1994, also from Pakistan. The now extinct whale Ambulocetus natans ("the walking whale that swam") lived in the Tethys Sea 49 million years ago. It lived around 3 million years after Pakicetus but 9 million before Basilosaurus. The fossil luckily includes a good portion of the hind legs. The legs were strong and ended in long feet very much like those of a modern pinniped. The legs were certainly functional both on land and at sea. The whale retained a tail and lacked a fluke, the major means of locomotion in modern cetaceans. The structure of the backbone shows, however, that Ambulocetus swam like modern whales by moving the rear portion of its body up and down, even though a fluke was missing. The large hind legs were used for propulsion in water. On land, where it probably bred and gave birth, Ambulocetus may have moved around very much like a modern sea lion. It was undoubtedly a whale that linked life on land with life at sea
1. Fluke: the two parts that constitute the large triangular tail of a whale
2. Blowhole: a hole in the top of the head used for breathing
阅读题目在这里!!!
Paragraph 1: It should be obvious that cetaceans—whales, porpoises, and dolphins—are mammals. They breathe through lungs, not through gills, and give birth to live young. Their streamlined bodies, the absence of hind legs, and the presence of a fluke1 and blowhole2 cannot disguise their affinities with land dwelling mammals. However, unlike the cases of sea otters and pinnipeds (seals, sea lions, and walruses, whose limbs are functional both on land and at sea), it is not easy to envision what the first whales looked like. Extinct but already fully marine cetaceans are known from the fossil record. How was the gap between a walking mammal and a swimming whale bridged? Missing until recently were fossils clearly intermediate, or transitional, between land mammals and cetaceans.
1. In paragraph 1, what does the author say about the presence of a blowhole in cetaceans?
○It clearly indicates that cetaceans are mammals.
○It cannot conceal the fact that cetaceans are mammals.
○It is the main difference between cetaceans and land-dwelling mammals.
○It cannot yield clues about the origins of cetaceans.
解析：答案是(2)
由the presence of a blowhole in cetaceans定位到 Their streamlined bodies, the absence of hind legs, and the presence of a fluke and blowhole cannot disguise their affinities with land dwelling mammals. 所以是在说这些身体结构不能掩盖它们好陆生哺乳动物的亲缘关系。假设对于这句话根本不理解，就往前看，第一句直到定位句，这些部分的结构关系是：It should be obvious that cetaceans—whales, porpoises, and dolphins—are mammals是主要论述句，后面两句则是解释论述句的。所以这句话肯定在讲cetaceans怎么就很明显是哺乳动物了。结合肯定理解的部分：”不能。。。它们与哺乳动物的关系”得出答案。
考点：带解释的论述句，或者往大了说就是在考察句子之间的逻辑关系。
2. Which of the following can be inferred from paragraph 1 about early sea otters?
○It is not difficult to imagine what they looked like.
○There were great numbers of them.
○They lived in the sea only.
○They did not leave many fossil remains.
解析：答案是(1)
由early sea otters定位到However, unlike the cases of sea otters and pinnipeds (seals, sea lions, and walruses, whose limbs are functional both on land and at sea), it is not easy to envision what the first whales looked like.正推。
考点：ETS给出专业解释的部分出考题可能性大(seals, sea lions, and walruses, whose limbs are functional both on land and at sea)
Paragraph 3: The fossil consists of a complete skull of an archaeocyte, an extinct group of ancestors of modern cetaceans. Although limited to a skull, the Pakicetus fossil provides precious details on the origins of cetaceans. The skull is cetacean-like but its jawbones lack the enlarged space that is filled with fat or oil and used for receiving underwater sound in modern whales. Pakicetus probably detected sound through the ear opening as in land mammals. The skull also lacks a blowhole, another cetacean adaptation for diving. Other features, however, show experts that Pakicetus is a transitional form between a group of extinct flesh-eating mammals, the mesonychids, and cetaceans. It has been suggested that Pakicetus fed on fish in shallow water and was not yet adapted for life in the open ocean. It probably bred and gave birth on land.
3. The word “precious” in the passage is closest in meaning to
○exact
○scarce
○valuable
○initial
解析：答案是(3)
Although limited to a skull, the Pakicetus fossil provides precious details on the origins of cetaceans.尽管只是限于研究skull，Pakicetus还是提供了……的细节证据。按照逻辑，单词应该是有积极倾向的词，从1.3里选，exact精确，如果想要表现如何精确，应该出现数字神马的吧!
考点：句间逻辑。
4. Pakicetus and modern cetaceans have similar
○hearing structures
○adaptations for diving
○skull shapes
○breeding locations
解析：答案是(3)
定位到The skull is cetacean-like but its jawbones lack the enlarged space that is filled with fat or oil and used for receiving underwater sound in modern whales.这里有两者的对比：外形一致，但是缺少enlarged space。
考点：对比。
5. The word “It” in the passage refers to
○Pakicetus
○fish
○life
○ocean
解析：答案是(1)
It has been suggested that Pakicetus fed on fish in shallow water and was not yet adapted for life in the open ocean. It probably bred and gave birth on land.
看动作发出bred and gave birth，肯定是1,2里面选，前面是在说Pakicetus,所以选1。
考点：代词还原
Paragraph 4: Another major discovery was made in Egypt in 1989. Several skeletons of another early whale, Basilosaurus, were found in sediments left by the Tethys Sea and now exposed in the Sahara desert. This whale lived around 40 million years ago, 12 million years after Pakicetus. Many incomplete skeletons were found but they included, for the first time in an archaeocyte, a complete hind leg that features a foot with three tiny toes. Such legs would have been far too small to have supported the 50-foot-long Basilosaurus on land. Basilosaurus was undoubtedly a fully marine whale with possibly nonfunctional, or vestigial, hind legs.
6. The word “exposed” in the passage is closest in meaning to
○explained
○visible
○identified
○located
解析：答案是(2)
Several skeletons of another early whale, Basilosaurus, were found in sediments left by the Tethys Sea and now exposed in the Sahara desert.
在沉积物中发现，现在……露出来了。
考点： 对比，now。
7. The hind leg of Basilosaurus was a significant find because it showed that Basilosaurus
○lived later than Ambulocetus natans
○lived at the same time as Pakicetus
○was able to swim well
○could not have walked on land
解析；答案是(4)
“Such legs would have been far too small to have supported the 50-foot-long Basilosaurus on land”，骨架的后肢太小以至于不能支撑其巨大身躯在陆地生活。“Basilosaurus was undoubtedly a fully marine whale with possibly nonfunctional, or vestigial, hind legs.”文章接着指出，它绝对是完全的海洋生物，其后肢很可能已不再具有实用功能。因此，后肢(hind leg)之所以是重大发现正是因为它向人们表明Basilosaurus不可能生活在陆地且一定为海洋生物。
8. It can be inferred that Basilosaurus bred and gave birth in which of the following locations
○On land
○Both on land and at sea
○In shallow water
○In a marine environment
解析：答案是(4)
段落结尾已明确指出“Basilosaurus was undoubtedly a fully marine whale”(Basilosaurus是进化完全的海洋鲸类)，因此B的一切活动都必然在海洋中，包括繁殖。
Paragraph 5: An even more exciting find was reported in 1994, also from Pakistan. The now extinct whale Ambulocetus natans ("the walking whale that swam") lived in the Tethys Sea 49 million years ago. It lived around 3 million years after Pakicetus but 9 million before Basilosaurus. The fossil luckily includes a good portion of the hind legs. The legs were strong and ended in long feet very much like those of a modern pinniped. The legs were certainly functional both on land and at sea. The whale retained a tail and lacked a fluke, the major means of locomotion in modern cetaceans. The structure of the backbone shows, however, that Ambulocetus swam like modern whales by moving the rear portion of its body up and down, even though a fluke was missing. The large hind legs were used for propulsion in water. On land, where it probably bred and gave birth, Ambulocetus may have moved around very much like a modern sea lion. It was undoubtedly a whale that linked life on land with life at sea.
9. Why does the author use the word “luckily” in mentioning that the Ambulocetus natans fossil included hind legs？
○Fossil legs of early whales are a rare find.
○The legs provided important information about the evolution of cetaceans.
○The discovery allowed scientists to reconstruct a complete skeleton of the whale.
○Until that time, only the front legs of early whales had been discovered.
解析：答案是(2)
The fossil luckily includes a good portion of the hind legs. 之后在讲的都是the legs怎样怎样，得到哪些与现代动物的比较，所以，选(2)。而且，关于作者目的的题目一定是和主题相关的，或者全文主旨，或者段落主旨。
考点：主旨。
10. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.
○Even though Ambulocetus swam by moving its body up and down, it did not have a backbone.
○The backbone of Ambulocetus, which allowed it to swim, provides evidence of its missing fluke.
○Although Ambulocetus had no fluke, its backbone structure shows that it swam like modern whales.
○By moving the rear parts of their bodies up and down, modern whales swim in a different way from the way Ambulocetus swam.
解析：答案是(3)
The structure of the backbone shows, however, that Ambulocetus swam like modern whales by moving the rear portion of its body up and down, even though a fluke was missing.
句子的主要逻辑是even though让步
考点：句子逻辑
11. The word “propulsion” in the passage is closest in meaning to
○staying afloat
○changing direction
○decreasing weight
○moving forward
解析：答案是(4)
从前一句中“Ambulocetus swam like modern whales”也可推断propulsion与 swim相关，应为“向前游动”
Extinct but already fully marine cetaceans are known from the fossil record. ■How was the gap between a walking mammal and a swimming whale bridged? ■Missing until recently were fossils clearly intermediate, or transitional, between land mammals and cetaceans.
■Very exciting discoveries have finally allowed scientists to reconstruct the most likely origins of cetaceans. ■In 1979, a team looking for fossils in northern Pakistan found what proved to be the oldest fossil whale. The fossil was officially named Pakicetus in honor of the country where the discovery was made. Pakicetus was found embedded in rocks formed from river deposits that were 52 million years old. The river that formed these deposits was actually not far from an ancient ocean known as the Tethys Sea.
12. Look at the four squares [■] that indicate where the following sentence can be added to the passage.
This is a question that has puzzled scientists for ages.
Where would the sentence best fit?
解析：答案是(2)
This is a question，前面得有一个问题。所以在How was the gap between a walking mammal and a swimming whale bridged? 之后，但不能急于选(2)，可能不会这么简单。再看一下后面一句，后面却是和这句话逻辑关联不大，所以确定答案。
考点：句简逻辑。
13. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some answer choices do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.
This passage discusses fossils that help to explain the likely origins of cetaceans—whales, porpoises, and dolphins.
●
●
●
Answer Choices
○Recent discoveries of fossils have helped to show the link between land mammals and cetaceans.
○The discovery of Ambulocetus natans provided evidence for a whale that lived both on land and at sea.
○The skeleton of Basilosaurus was found in what had been the Tethys Sea, an area rich in fossil evidence.
○Pakicetus is the oldest fossil whale yet to be found.
○Fossils thought to be transitional forms between walking mammals and swimming whales were found.
○Ambulocetus' hind legs were used for propulsion in the water.
解析：答案是(1,2,5)
1选项“近期化石发现帮助科学家推断陆生哺乳动物与鲸类的联系”。文章正是讨论三大化石发现如何帮助科学研究者推断两种物种的进化，因此1正确；
2选项“Ambulocetus natans化石是水陆两栖的过渡阶段鲸类”。第5段主旨内容。
3选项“Basilosaurus化石发现于T海，此处富含化石”，此为细节信息，不属于总结内容
4选项“P化石是最古老的鲸类化石”，属于细节信息，与文章主要内容无关，错误；
5选项“处于陆生哺乳动物和鲸类过渡阶段的化石被发现”，即指Ambulocetus natans化石，正确；
6“Ambulocetus natans化石的后肢用于水中驱动”，属于细节信息，与文章主要内容无关，错误。
以上就是关于TPO2 The Origins of Cetaceans的阅读题目解析，希望对大家的备考有所帮助。前程百利祝大家都能取得理想的考试成绩。
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