2013年托福考试阅读材料专题训练6_第2页

Paragraph 1: 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.

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?

13-14. 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.
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Answer Choices
1. Recent discoveries of fossils have helped to show the link between land mammals and cetaceans.
2. The discovery of Ambulocetus natans provided evidence for a whale that lived both on land and at sea.
3. The skeleton of Basilosaurus was found in what had been the Tethys Sea, an area rich in fossil evidence.
4. Pakicetus is the oldest fossil whale yet to be found.
5. Fossils thought to be transitional forms between walking mammals and swimming whales were found.
6. Ambulocetus' hind legs were used for propulsion in the water.
 
参考答案
1. ○2
This is a Factual Information question asking for specific information that can be found in paragraph 1. Choice 2 is the best answer. It is essentially a rephrasing of the statement in paragraph 1 that blowholes cannot disguise cetaceans’ affinities with other mammals. The other three choices are refuted, either directly or indirectly, by that paragraph.

1. ○1
This is an Inference question asking for information that can be inferred from paragraph 1 . Choice 1 is the best answer because paragraph 1 says that sea otters are unlike early mammals whose appearances are not easy to imagine. By inference, then, the early appearance of sea otters must be easy (or not difficult) to imagine.

2. ○3
This is a Vocabulary question. The word being tested is precious. It is highlighted in the passage. The correct answer is choice 3, "valuable." Anything that is precious is very important and therefore valuable.

3. ○3
This is a Factual Information question asking for specific information that can be found in the passage. Choice 3 is the best answer. Paragraph 3 describes the differences and similarities between Pakicetus and modern cetaceans. Sentence 3 of that paragraph states that their skulls are similar. The other three choices describe differences, not similarities.

4. ○1
This is a Reference question. The word being tested is It. That word is highlighted in the passage. This is a simple pronoun referent item. Choice I , "Pakicetus" is the correct answer. The word It here refers to a creature that probably bred and gave birth on land. Pakicetus is the only one of the choices to which this could apply.

5. ○2
This is a Vocabulary question. The word being tested is exposed. It is highlighted in the passage. The correct answer is choice 2, "visible." Exposed means "uncovered." A skeleton that is uncovered can be seen. Visible means "can be seen."

6. ○ 4
This is a Factual Information question asking for specific information that can be found in the passage. Choice 4 is the best answer because it is the only detail about the skeleton of Basilosaurus mentioned in paragraph 4, meaning that it is significant. Choice 1 is true, but it is not discussed in the detail that choice 4 is, and does not represent the significance of the discovery. Choice 3 is not mentioned, and choice 2 is not :me.

7. ○4
    This is an Inference question asking for a conclusion that can be drawn from the entire passage. Choice 4 is the best answer based on the last sentence of paragraph 4, which describes Basilosaurus as a fully marine whale. That implies that everything it did, including breeding and giving birth, could have been done only in a marine environment.

8. ○2
    This is an Inference question asking for a conclusion that can be drawn from the passage. Paragraph 5 explains that this discovery provided important information to scientists that they might not have been able to obtain without it. Therefore, you can infer that the discovery was a "lucky" one. The passage offers no support for the other choices. Therefore, choice 2 is the best answer.

10. ○3
This is a Sentence Simplification question. As with all of these items, a single sentence in the passage is highlighted:
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.
Choice 3 is the best answer because it contains all of the essential information in the highlighted sentence. Choice 1 is not true because Ambulocetus did have a backbone. Choice 2 is not true because the sentence says that the backbone showed how the Ambulocetus swam, not that it was missing a fluke. Choice 4 is untrue because the sentence states that Ambulocetus and modern whales swam in the same way.

11. ○4
This is a Vocabulary question. The word being tested is propulsion. It is highlighted in the passage. Choice 4, "moving forward" is the best answer because it means the action of propelling. The whale in the sentence used its hind legs to push itself forward in the water.

12. ○2
This is an Insert Text question. You can see the four black squares in paragraphs 1 and 2 that represent the possible answer choices here.
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 sentence provided is "This is a question that has puzzled scientists for ages." The best place to insert it is at square 2. The sentence that precedes square 2 is in the form of a rhetorical question and the inserted sentence explicitly provides a response to it. None of the other sentences preceding squares is a question, so the inserted sentence cannot logically follow any one of them.

13-14. ○1 2 5
 
参考译文

众所周知，鲸类动物是哺乳动物,如鲸鱼、鼠海豚和海豚。它们用肺呼吸，而不是鳃，属于胎生。鲸类动物呈流线型的身体，后腿的消失，尾片和气孔的出现，这些特征都不能掩饰它们和陆生哺乳动物的相似之处。然而，想知道世上第一只鲸长什么样并非易事，不像还原海獭及鳍足类动物（四肢水陆两用如海豹，海狮，海象）的原貌那么简单。一些完全水生的鲸类动物虽然已经灭绝，但仍可通过化石来对它们进行考察。陆栖哺乳动物和海洋鲸类之间有何联系？近期发现的化石已经可以很清晰地帮助人们了解这个问题，以及他们之间的过渡关系。

科学家们通过一些令人振奋的发现重现了鲸类动物几近真实的起源。1979年，在巴基斯坦北部，一个寻找化石的考察队发掘到了最古老的鲸鱼化石。这块化石被官方命名为 Pakicifus，以纪念人们发现它的地方。这块化石是在一条河的沉积岩中发现的，这条河有5200万年的历史，离古地中海不远

Pakicifus包括一个完整原始动物的头盖骨，它的主人是现代鲸类的祖先。尽管只是个头盖骨，但它却提供了研究原始鲸类动物起源的珍贵信息。这个头盖骨和鲸类动物的很像，但它的下颌骨和现代鲸类略有不同，现代鲸类动物的下颌骨中含有额外的空间储存脂肪或者油脂来吸收水下的声音。Pakicifus的主人可能会像陆生哺乳动物那样通过张开的耳朵来探测声音。另外，这个头盖骨没有呼吸孔，而鲸类动物有，这便是鲸类动物为了适应水生环境的另一种适应性表现。然而，专家认为Pakicifus的其它特征表明它们是已灭绝的食肉哺乳动物（中兽科动物）和鲸类动物的过渡型。有人认为Pakicifus 靠吃浅水的鱼类为生，未能适应在辽阔的大海里生活。它们很有可能在陆地进行生育繁殖。

1989年，在埃及有了另一个重大发现。人们在古地中海残留的沉积物中发现了另一类早期鲸鱼Basilosaurus的一些骨骸，这些骨骸如今暴露在撒哈拉大沙漠上。Basilosaurus生活在大约4000万年前，比Pakicifus鲸鱼晚了1200万年。尽管发现的这些骨骼并不完整，但这是专家们第一次在原始动物身上发现完整的后肢，它有三个小脚趾作为的足部特征。可这些后肢还太小，远无法支撑50英尺长的Basilosaurus在陆地行走。因此，Basilosaurus必定是完全水生的鲸鱼，它们的后肢已经不起任何作用，或者说已经退化
 
1994年，巴基斯坦报道了一个更令人兴奋的发现。目前已经灭绝的鲸鱼Ambulocetus natans（可以步行的鲸类）4900万年前曾在古地中海生活过。比Pakicetus晚大约 300万年，比Basilosaurus早 900万年左右。幸运的是，被发现的Ambulocetus natans保留着完整的后肢。它的后肢很强壮，底部有长足，非常像现在的鳍足类动物。这些后肢使得他们既能在陆地行走又能在海里游行。虽然Ambulocetus natans保留了尾巴，但它们缺少现代水生鲸类动物用于行动的主要身体部位——尾片。不过，从Ambulocetus的脊椎结构上可以看出，即使缺少尾片，它们也能像现代鲸鱼那样通过身体背部的上下摆动来游走。大的后肢通常被当作是水中前行的发动机。在它们可能交配繁殖的陆地上，Ambulocetus行动起来非常像现代海狮。毫无疑问，鲸鱼是连接着陆地生命和海洋生命的物种。