文章及題目
（本篇為OG/Practice Site1）
THE ORIGINS OF CETACEANS
→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.
→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.
→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.
→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.
→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
Fluke: the two parts that constitute the large triangular tail of a whale
1.
"Blowhole: a hole in the top of the head used for breathing
→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 fluke3 and blowhole4 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.
Directions: Mark your answer by filling in the oval next to your choice.
1. In paragraph 1, what does the author say about the presence of a blowhole in cetaceans?
A.Staying afloat
B.Changing direction
C.Decreasing weight
D.Moving forward
2. Which of the following can be inferred from paragraph 1 about early sea otters?
A.It is not difficult to imagine what they looked like
B.There were great numbers of them.
C.They lived in the sea only.
D.They did not leave many fossil remains.
→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
A.Exact
B.Scarce
C.Valuable
D.Initial
4. Pakicetus and modern cetaceans have similar
A.Hearing structures
B.Adaptations for diving
C.Skull shapes
D.Breeding locations
5. The word it in the passage refers to
A.Pakicetus
B.Fish
C.Life
D.ocean
→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
A.Explained
B.Visible
C.Identified
D.Located
7. The hind leg of Basilosaurus was a significant find because it showed that Basilosaurus
A.Lived later than Ambulocetus natans
B.Lived at the same time as Pakicetus
C.Was able to swim well
D.Could not have walked on land
8. It can be inferred that Basilosaurus bred and gave birth in which of the following locations
A.On land
B.Both on land and at sea
C.In shallow water
D.In a marine environment
→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?
A.Fossil legs of early whales are a rare find.
B.The legs provided important information about the evolution of cetaceans.
C.The discovery allowed scientists to reconstruct a complete skeleton of the whale.
D.Until that time, only the front legs of early whales had been discovered.
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.
A.Even though Ambulocetus swam by moving its body up and down, it did not have a backbone.
B.The backbone of Ambulocetus, which allowed it to swim, provides evidence of its missing fluke.
C.Although Ambulocetus had no fluke, its backbone structure shows that it swam like modern whales.
D.By moving the rear parts of their bodies up and down, modern whales swim in a different way from the way Ambulocetus swam.
11. The word propulsion in the passage is closest in meaning to
A.Staying afloat
B.Changing direction
C.Decreasing weight
D.Moving forward
→Paragraph 1: Extinct but already fully marine cetaceans are known from the fossil record. ■(A)How was the gap between a walking mammal and a swimming whale bridged? ■(B)Missing until recently were fossils clearly intermediate, or transitional, between land mammals and cetaceans.■(C)Very exciting discoveries have finally allowed scientists to reconstruct the most likely origins of cetaceans. ■(D)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 cetaceanswhales, 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 Basilosaurusw as 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.
l 文章逐句翻譯
第一段：
It should be obvious that cetaceans-whales, porpoises, and dolphins-are mammals.
顯而易見，鯨目動(dòng)物，鯨魚，鼠海豚，和海豚等屬于哺乳動(dòng)物。
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.
他們通過肺部，而不是鰓呼吸，并且直接生育有生命的下一代。流線型的身體，退化的后足，以及fluke和氣孔的存在不能掩蓋它們和陸生哺乳動(dòng)物的親緣關(guān)系。
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. 然而，跟海獺和鰭足類動(dòng)物（海豹，海獅和海象等四肢都在陸地和海上）的情況不同，很難想象最初的鯨類動(dòng)物的模樣。
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.
滅絕的完全海洋鯨類已經(jīng)在化石記錄中被發(fā)現(xiàn)。鯨魚是如何從陸生哺乳動(dòng)物過渡進(jìn)化到海生哺乳動(dòng)物的？直到最近，清晰表現(xiàn)鯨魚在從陸生哺乳動(dòng)物到海生哺乳動(dòng)物過渡時(shí)期的化石才被發(fā)現(xiàn)。
第二段：
Very exciting discoveries have finally allowed scientists to reconstruct the most likely origins of cetaceans.
這項(xiàng)非常令人興奮的發(fā)現(xiàn)終于使科學(xué)家們能夠重建鯨目動(dòng)物最有可能的起源。
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.
1979年，一個(gè)小組在巴基斯坦北部地區(qū)找到了被證明是最古老的鯨魚的化石。該化石被正式命名為Pakicetus，以紀(jì)念化石被發(fā)現(xiàn)所在的國家。
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.
Pakicetus被發(fā)現(xiàn)時(shí)被嵌在已有5200萬年歷史的河流沉積物形成的巖石中。形成這些沉積物的河流實(shí)際上離一個(gè)古海洋不遠(yuǎn)，那個(gè)古海洋即是特提斯海。
第三段：
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.
化石包括一具archaeocyte（現(xiàn)代鯨類動(dòng)物的祖先的已滅絕的一種）的完整頭骨。雖然僅是一具頭骨，化石Pakicetus為鯨類動(dòng)物的起源提供了珍貴的細(xì)節(jié)。
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.
頭骨是鯨類動(dòng)物的頭骨，但是與現(xiàn)代鯨類動(dòng)物的頭骨相比，其顎骨缺乏用于接收水下聲音的充滿脂肪或油的擴(kuò)大的空間
Pakicetus probably detected sound through the ear opening as in land mammals. The skull also lacks a blowhole, another cetacean adaptation for diving.
Pakicetus可能是開放的耳朵來偵測聲音，正如陸生哺乳動(dòng)物那樣。頭骨也缺乏一個(gè)氣孔，而氣孔是又一個(gè)鯨類動(dòng)物用于潛水的適應(yīng)性進(jìn)化。
Other features, however, show experts that Pakicetus is a transitional form between a group of extinct flesh-eating mammals, the mesonychids, and cetaceans.
但是，專家發(fā)現(xiàn)，其他特征顯示Pakicetus是一種介于中爪獸（一種已滅絕的食肉哺乳動(dòng)物）和鯨類動(dòng)物的過渡形式。
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.
這已經(jīng)暗示，Pakicetus是以淺水魚為食并且尚未適應(yīng)開放海洋的生活。它可能在陸地上繁殖和生育。
第四段：
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.
另一個(gè)重大發(fā)現(xiàn)發(fā)生于1989年的埃及。幾塊龍王鯨（另一種早期鯨魚）的骨骼被發(fā)現(xiàn)于特提斯海遺留下的沉積物中，并且現(xiàn)在在撒哈拉沙漠暴露出來。
This whale lived around 40 million years ago, 12 million years after. 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.
這種鯨魚生活在大約4千萬年前，比Pakicetus晚了1200萬年。許多不完整的骨骼被發(fā)現(xiàn)，但其中包括一個(gè)在archaeocyte中首次發(fā)現(xiàn)的一個(gè)帶有三個(gè)微小腳趾的起腳的作用的完整的后腿。
Such legs would have been far too small to have supported the 50-foot-long Basilosaurus on land.
這樣的腿本來太小，遠(yuǎn)不足以支撐生活在陸地上的的50英尺長的龍王鯨。
Basilosaurus was undoubtedly a fully marine whale with possibly nonfunctional, or vestigial, hind legs.
龍王鯨是無疑是一個(gè)具有可能無功能的，或者說退化后肢的完全海洋鯨魚。
第五段：
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.
一個(gè)更令人激動(dòng)的發(fā)現(xiàn)是在1994年報(bào)道的，也來自巴基斯坦。已滅絕的走鯨（“會(huì)游泳的走動(dòng)鯨魚”） 生活在四千九百萬年前的特提斯海洋。它生活在Pakicetus之后約3百萬年的時(shí)期，但是比龍王鯨早9百萬年。
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.
幸運(yùn)的是，化石包括了后腿的一個(gè)完好部分。這些腿很強(qiáng)壯并且有著長腳，這和現(xiàn)代鰭足類動(dòng)物很像。
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.
這些腿肯定在陸地及海里都能發(fā)揮作用。這種鯨魚保留了尾巴（現(xiàn)代鯨類動(dòng)物運(yùn)動(dòng)的主要結(jié)構(gòu)），但是沒有fluke。
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.
但是，脊椎的結(jié)構(gòu)顯示，即使缺少fluke，走鯨通過上下移動(dòng)其身體后部游動(dòng)，這一點(diǎn)類似于現(xiàn)代鯨類動(dòng)物。
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
巨大的后腿被用于在水中推進(jìn)。在它們可能繁殖及生育的陸地上，走鯨可能生活得很像現(xiàn)代的海獅了。這無疑是聯(lián)系陸生生命與海生生命的一種鯨魚。
（本篇為OG/Practice Site1）
THE ORIGINS OF CETACEANS
→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.
→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.
→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.
→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.
→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
Fluke: the two parts that constitute the large triangular tail of a whale
1.
"Blowhole: a hole in the top of the head used for breathing
→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 fluke3 and blowhole4 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.
Directions: Mark your answer by filling in the oval next to your choice.
1. In paragraph 1, what does the author say about the presence of a blowhole in cetaceans?
A.Staying afloat
B.Changing direction
C.Decreasing weight
D.Moving forward
2. Which of the following can be inferred from paragraph 1 about early sea otters?
A.It is not difficult to imagine what they looked like
B.There were great numbers of them.
C.They lived in the sea only.
D.They did not leave many fossil remains.
→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
A.Exact
B.Scarce
C.Valuable
D.Initial
4. Pakicetus and modern cetaceans have similar
A.Hearing structures
B.Adaptations for diving
C.Skull shapes
D.Breeding locations
5. The word it in the passage refers to
A.Pakicetus
B.Fish
C.Life
D.ocean
→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
A.Explained
B.Visible
C.Identified
D.Located
7. The hind leg of Basilosaurus was a significant find because it showed that Basilosaurus
A.Lived later than Ambulocetus natans
B.Lived at the same time as Pakicetus
C.Was able to swim well
D.Could not have walked on land
8. It can be inferred that Basilosaurus bred and gave birth in which of the following locations
A.On land
B.Both on land and at sea
C.In shallow water
D.In a marine environment
→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?
A.Fossil legs of early whales are a rare find.
B.The legs provided important information about the evolution of cetaceans.
C.The discovery allowed scientists to reconstruct a complete skeleton of the whale.
D.Until that time, only the front legs of early whales had been discovered.
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.
A.Even though Ambulocetus swam by moving its body up and down, it did not have a backbone.
B.The backbone of Ambulocetus, which allowed it to swim, provides evidence of its missing fluke.
C.Although Ambulocetus had no fluke, its backbone structure shows that it swam like modern whales.
D.By moving the rear parts of their bodies up and down, modern whales swim in a different way from the way Ambulocetus swam.
11. The word propulsion in the passage is closest in meaning to
A.Staying afloat
B.Changing direction
C.Decreasing weight
D.Moving forward
→Paragraph 1: Extinct but already fully marine cetaceans are known from the fossil record. ■(A)How was the gap between a walking mammal and a swimming whale bridged? ■(B)Missing until recently were fossils clearly intermediate, or transitional, between land mammals and cetaceans.■(C)Very exciting discoveries have finally allowed scientists to reconstruct the most likely origins of cetaceans. ■(D)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 cetaceanswhales, 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 Basilosaurusw as 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.
l 文章逐句翻譯
第一段：
It should be obvious that cetaceans-whales, porpoises, and dolphins-are mammals.
顯而易見，鯨目動(dòng)物，鯨魚，鼠海豚，和海豚等屬于哺乳動(dòng)物。
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.
他們通過肺部，而不是鰓呼吸，并且直接生育有生命的下一代。流線型的身體，退化的后足，以及fluke和氣孔的存在不能掩蓋它們和陸生哺乳動(dòng)物的親緣關(guān)系。
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. 然而，跟海獺和鰭足類動(dòng)物（海豹，海獅和海象等四肢都在陸地和海上）的情況不同，很難想象最初的鯨類動(dòng)物的模樣。
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.
滅絕的完全海洋鯨類已經(jīng)在化石記錄中被發(fā)現(xiàn)。鯨魚是如何從陸生哺乳動(dòng)物過渡進(jìn)化到海生哺乳動(dòng)物的？直到最近，清晰表現(xiàn)鯨魚在從陸生哺乳動(dòng)物到海生哺乳動(dòng)物過渡時(shí)期的化石才被發(fā)現(xiàn)。
第二段：
Very exciting discoveries have finally allowed scientists to reconstruct the most likely origins of cetaceans.
這項(xiàng)非常令人興奮的發(fā)現(xiàn)終于使科學(xué)家們能夠重建鯨目動(dòng)物最有可能的起源。
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.
1979年，一個(gè)小組在巴基斯坦北部地區(qū)找到了被證明是最古老的鯨魚的化石。該化石被正式命名為Pakicetus，以紀(jì)念化石被發(fā)現(xiàn)所在的國家。
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.
Pakicetus被發(fā)現(xiàn)時(shí)被嵌在已有5200萬年歷史的河流沉積物形成的巖石中。形成這些沉積物的河流實(shí)際上離一個(gè)古海洋不遠(yuǎn)，那個(gè)古海洋即是特提斯海。
第三段：
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.
化石包括一具archaeocyte（現(xiàn)代鯨類動(dòng)物的祖先的已滅絕的一種）的完整頭骨。雖然僅是一具頭骨，化石Pakicetus為鯨類動(dòng)物的起源提供了珍貴的細(xì)節(jié)。
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.
頭骨是鯨類動(dòng)物的頭骨，但是與現(xiàn)代鯨類動(dòng)物的頭骨相比，其顎骨缺乏用于接收水下聲音的充滿脂肪或油的擴(kuò)大的空間
Pakicetus probably detected sound through the ear opening as in land mammals. The skull also lacks a blowhole, another cetacean adaptation for diving.
Pakicetus可能是開放的耳朵來偵測聲音，正如陸生哺乳動(dòng)物那樣。頭骨也缺乏一個(gè)氣孔，而氣孔是又一個(gè)鯨類動(dòng)物用于潛水的適應(yīng)性進(jìn)化。
Other features, however, show experts that Pakicetus is a transitional form between a group of extinct flesh-eating mammals, the mesonychids, and cetaceans.
但是，專家發(fā)現(xiàn)，其他特征顯示Pakicetus是一種介于中爪獸（一種已滅絕的食肉哺乳動(dòng)物）和鯨類動(dòng)物的過渡形式。
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.
這已經(jīng)暗示，Pakicetus是以淺水魚為食并且尚未適應(yīng)開放海洋的生活。它可能在陸地上繁殖和生育。
第四段：
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.
另一個(gè)重大發(fā)現(xiàn)發(fā)生于1989年的埃及。幾塊龍王鯨（另一種早期鯨魚）的骨骼被發(fā)現(xiàn)于特提斯海遺留下的沉積物中，并且現(xiàn)在在撒哈拉沙漠暴露出來。
This whale lived around 40 million years ago, 12 million years after. 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.
這種鯨魚生活在大約4千萬年前，比Pakicetus晚了1200萬年。許多不完整的骨骼被發(fā)現(xiàn)，但其中包括一個(gè)在archaeocyte中首次發(fā)現(xiàn)的一個(gè)帶有三個(gè)微小腳趾的起腳的作用的完整的后腿。
Such legs would have been far too small to have supported the 50-foot-long Basilosaurus on land.
這樣的腿本來太小，遠(yuǎn)不足以支撐生活在陸地上的的50英尺長的龍王鯨。
Basilosaurus was undoubtedly a fully marine whale with possibly nonfunctional, or vestigial, hind legs.
龍王鯨是無疑是一個(gè)具有可能無功能的，或者說退化后肢的完全海洋鯨魚。
第五段：
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.
一個(gè)更令人激動(dòng)的發(fā)現(xiàn)是在1994年報(bào)道的，也來自巴基斯坦。已滅絕的走鯨（“會(huì)游泳的走動(dòng)鯨魚”） 生活在四千九百萬年前的特提斯海洋。它生活在Pakicetus之后約3百萬年的時(shí)期，但是比龍王鯨早9百萬年。
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.
幸運(yùn)的是，化石包括了后腿的一個(gè)完好部分。這些腿很強(qiáng)壯并且有著長腳，這和現(xiàn)代鰭足類動(dòng)物很像。
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.
這些腿肯定在陸地及海里都能發(fā)揮作用。這種鯨魚保留了尾巴（現(xiàn)代鯨類動(dòng)物運(yùn)動(dòng)的主要結(jié)構(gòu)），但是沒有fluke。
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.
但是，脊椎的結(jié)構(gòu)顯示，即使缺少fluke，走鯨通過上下移動(dòng)其身體后部游動(dòng)，這一點(diǎn)類似于現(xiàn)代鯨類動(dòng)物。
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
巨大的后腿被用于在水中推進(jìn)。在它們可能繁殖及生育的陸地上，走鯨可能生活得很像現(xiàn)代的海獅了。這無疑是聯(lián)系陸生生命與海生生命的一種鯨魚。