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.
●
●
●
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.
 
參考答案
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
 
參考譯文

眾所周知，鯨類動物是哺乳動物,如鯨魚、鼠海豚和海豚。它們用肺呼吸，而不是鰓，屬于胎生。鯨類動物呈流線型的身體，后腿的消失，尾片和氣孔的出現(xiàn)，這些特征都不能掩飾它們和陸生哺乳動物的相似之處。然而，想知道世上第一只鯨長什么樣并非易事，不像還原海獺及鰭足類動物（四肢水陸兩用如海豹，海獅，海象）的原貌那么簡單。一些完全水生的鯨類動物雖然已經滅絕，但仍可通過化石來對它們進行考察。陸棲哺乳動物和海洋鯨類之間有何聯(lián)系？近期發(fā)現(xiàn)的化石已經可以很清晰地幫助人們了解這個問題，以及他們之間的過渡關系。

科學家們通過一些令人振奮的發(fā)現(xiàn)重現(xiàn)了鯨類動物幾近真實的起源。1979年，在巴基斯坦北部，一個尋找化石的考察隊發(fā)掘到了最古老的鯨魚化石。這塊化石被官方命名為 Pakicifus，以紀念人們發(fā)現(xiàn)它的地方。這塊化石是在一條河的沉積巖中發(fā)現(xiàn)的，這條河有5200萬年的歷史，離古地中海不遠

Pakicifus包括一個完整原始動物的頭蓋骨，它的主人是現(xiàn)代鯨類的祖先。盡管只是個頭蓋骨，但它卻提供了研究原始鯨類動物起源的珍貴信息。這個頭蓋骨和鯨類動物的很像，但它的下頜骨和現(xiàn)代鯨類略有不同，現(xiàn)代鯨類動物的下頜骨中含有額外的空間儲存脂肪或者油脂來吸收水下的聲音。Pakicifus的主人可能會像陸生哺乳動物那樣通過張開的耳朵來探測聲音。另外，這個頭蓋骨沒有呼吸孔，而鯨類動物有，這便是鯨類動物為了適應水生環(huán)境的另一種適應性表現(xiàn)。然而，專家認為Pakicifus的其它特征表明它們是已滅絕的食肉哺乳動物（中獸科動物）和鯨類動物的過渡型。有人認為Pakicifus 靠吃淺水的魚類為生，未能適應在遼闊的大海里生活。它們很有可能在陸地進行生育繁殖。

1989年，在埃及有了另一個重大發(fā)現(xiàn)。人們在古地中海殘留的沉積物中發(fā)現(xiàn)了另一類早期鯨魚Basilosaurus的一些骨骸，這些骨骸如今暴露在撒哈拉大沙漠上。Basilosaurus生活在大約4000萬年前，比Pakicifus鯨魚晚了1200萬年。盡管發(fā)現(xiàn)的這些骨骼并不完整，但這是專家們第一次在原始動物身上發(fā)現(xiàn)完整的后肢，它有三個小腳趾作為的足部特征�？蛇@些后肢還太小，遠無法支撐50英尺長的Basilosaurus在陸地行走。因此，Basilosaurus必定是完全水生的鯨魚，它們的后肢已經不起任何作用，或者說已經退化
 
1994年，巴基斯坦報道了一個更令人興奮的發(fā)現(xiàn)。目前已經滅絕的鯨魚Ambulocetus natans（可以步行的鯨類）4900萬年前曾在古地中海生活過。比Pakicetus晚大約 300萬年，比Basilosaurus早 900萬年左右。幸運的是，被發(fā)現(xiàn)的Ambulocetus natans保留著完整的后肢。它的后肢很強壯，底部有長足，非常像現(xiàn)在的鰭足類動物。這些后肢使得他們既能在陸地行走又能在海里游行。雖然Ambulocetus natans保留了尾巴，但它們缺少現(xiàn)代水生鯨類動物用于行動的主要身體部位——尾片。不過，從Ambulocetus的脊椎結構上可以看出，即使缺少尾片，它們也能像現(xiàn)代鯨魚那樣通過身體背部的上下擺動來游走。大的后肢通常被當作是水中前行的發(fā)動機。在它們可能交配繁殖的陸地上，Ambulocetus行動起來非常像現(xiàn)代海獅。毫無疑問，鯨魚是連接著陸地生命和海洋生命的物種。