One of the mostsignificantevolutionaryevents that occurred on Earth was thetransitionof water-dwelling fish toterrestrialtetrapods (four-limbed organisms with backbones). Fish probably originated in the oceans, and our first records of them are inmarinerocks. However, by theDevonianPeriod (408 million to 362 million years ago), they had radiated into almost allavailableaquatichabitats, including freshwater settings. One of the groups whose fossils are especiallycommonin rocks deposited in fresh water is the lobe-finned fish.

The freshwaterDevonianlobe-finned fish rhipidistian crossopterygian is ofparticularinterestto biologists studyingtetrapodevolution. These fish lived in river channels and lakes on large deltas. Thedeltarocks in which these fossils are found are commonly reddueto oxidized iron minerals, indicating that the deltas formed in aclimatethat hadalternatewet and dry periods. If there were periods ofdrought, any adaptations allowing the fish tosurvivethe dry conditions would have beenadvantageous. In these rhipidistians，several such adaptations existed. It is known that they had lungs as well as gills forbreathing. Cross sections cutthroughsome of the fossilsrevealthat the mud filling theinteriorof thecarcassdiffered inconsistencyandtexturedepending on its location inside the fish. These differences suggest asaclikecavitybelow the front end of thegutthat can only be interpreted as a lung. Gills were undoubtedly the mainsourceofoxygenfor these fish, but the lungs served as anauxiliarybreathingdevicefor gulping air when the water becameoxygendepleted, such as during extended periods ofdrought. So, these fish had already evolved one of theprimerequisites for living on land: theabilityto use air as asourceofoxygen.

A secondadaptationof these fish was in the structure of the lobe fins. The fins were thick,fleshy, and quitesturdy, with a medianaxisof bone down the center. They could have been used asfeeblelocomotor devices on land, perhaps good enough to allow a fish to flop its way from one pool of water that was almost dry to anadjacentpond that had enough water andoxygenforsurvival. These finseventuallychanged into short,stubbylegs. The bones of the fins of aDevonianrhipidistian exactlymatchin number andpositionthelimbbones of the earliest known tetrapods, the amphibians. It should be emphasized that theevolutionof lungs and limbs was in nosensean anticipation of future life on land. These adaptations developed because they helped fish tosurvivein their existingaquaticenvironment.

Whatecologicalpressures might have caused fishes tograduallyabandontheir wateryhabitatand become increasingly land-dwelling creatures? Changes inclimateduring theDevonianmay have had something to do with this if freshwater areas became progressively morerestricted. Anotherimpetusmay have been new sources of food. The edges of ponds and streams surely hadscattereddead fish and other water-dwelling. Inaddition, plants had emerged intoterrestrialhabitats in areas near streams and ponds, and crabs and other arthropods were also members of this earliestterrestrialcommunity. Thus, by theDevonianthe landhabitatmarginal to freshwater was probably a richsourceofproteinthat could be exploited by an animal that could easily climb out of water. Evidencefrom teeth suggests that these earliest tetrapods did notutilizeland plants as food; they werepresumablycarnivorousand had not developed theabilityto feed on plants.

How did the first tetrapods make thetransitionto aterrestrialhabitat? Like early land plants such as rhyniophytes, they made only apartialtransition; they were still quite tied to water. However, many problems that faced early land plants were notapplicableto the first tetrapods. The ancestors of these animals already had acirculationsystem, and they weremobile, so that they could move to water to drink. Furthermore, they already had lungs, which rhipidistianspresumablyused forauxiliarybreathing. Theprincipalchanges for the earliest tetrapods were in theskeletalsystem—changes in the bones of the fins, thevertebralcolumn,pelvicgirdle, andpectoralgirdle.

Questions:
question_stem: Paragraph 1 supports which of the following statements about fish evolution?
choices: tag: A
text: Lobe-finned fish were among the earliest types of fish to appear.

tag: B
text: Fish began living in freshwater habitats only after originating elsewhere.

tag: C
text: Lobe-finned fish radiated into almost all available aquatic habitats.

tag: D
text: During the Devonian, lobe-finned fish were more common in marine than in freshwater habitats.
answer_key: B
explanation: 【题目翻译】第1段支持以下关于鱼类进化的哪些陈述？
A：叶鳍鱼是最早出现的鱼类之一。

B：鱼类开始生活在淡水栖息地后，才起源于其他地方。

C：叶鳍鱼辐射到几乎所有可用的水生栖息地。

D：在泥盆纪，有叶鳍的鱼在海洋中比在淡水栖息地中更常见。

【判定题型】：题目问的是文章中的具体细节信息，故根据题目问法可以判断本题为事实信息题。

【关键词定位】：根据关键词“ evolution”,定位到 Passage 1 第1句，原句为“One of the most significant evolutionary events that occurred on Earth was the transition of water-dwelling fish to terrestrial tetrapods (four-limbed organisms with backbones). ”，意思是“水中栖息的鱼类进化为陆地四足动物（有脊椎的四肢生物）是地球上发生过的重大进化事件之一。”。

【逻辑分析】第一段主要讲地球上最重要的演化之一是鱼从水生转型到陆生。鱼可能起源于海洋，我们最早的证据是在海洋的岩石里。但在 Devonian 时期，鱼开始基本都呈现水生形式包括淡水，其中一种化石特别普遍在淡水岩石里是 lobe-finned fish。

【选项分析】
选项 A 中 lobe-finned fish 显然不是最早的鱼类；错误
选项 B 与原文中鱼类出现的顺序阐述一致；正确
选项 C 中的 lobe-finned fish 只是其中的一种；错误
选项 D 中的 lobe-finned fish 是否在海洋比淡水中更普遍在原文中没有做对比。错误

question_stem: According to paragraph 2, what do the minerals in the delta rocks containing rhipidistian crossopterygian fossils reveal?
choices: tag: A
text: These deltas formed in dry periods but gradually became wetter.

tag: B
text: These deltas contain different types of iron minerals than do the surrounding areas.

tag: C
text: Most rhipidistian crossopterygian fish died when the climate became dry.

tag: D
text: Rhipidistian crossopterygian fish lived in areas that experienced alternate dry and wet periods.
answer_key: D
explanation: 【题目翻译】根据第2段，含有泥盆纪扇鳍鱼十字翼龙化石的三角洲岩石中的矿物揭示了什么？
A：这些三角洲形成于干旱期，但逐渐变湿。

B：这些三角洲比周围地区含有不同类型的铁矿物。

C：大部分的泥盆纪扇鳍鱼跨翅目鱼类在气候变干时死亡。

D：泥盆纪扇鳍鱼生活在干湿交替的地区。

【判定题型】：题目问的是文章中的具体细节信息，故根据题目问法可以判断本题为事实信息题。

【关键词定位】：根据关键词“delta rocks”,定位到 Passage 2，原句为“The delta rocks in which these fossils are found are commonly red due to oxidized iron minerals, indicating that the deltas formed in a climate that had alternate wet and dry periods. ”。意思是“发现这些化石的三角洲岩石通常由于铁矿物氧化而呈红色，这表明三角洲形成于干湿交替的气候中。”

【逻辑分析】根据第二段，很显然在三角洲的泥盆纪扇鳍鱼化石里的矿物质揭示了其生活的区域经历了干旱和潮湿交替的时期。

【选项分析】
A：文章中说的是干湿交替，而不是逐渐变湿。故选项错误。
B：文章说它们的化石常见于三角洲岩石中，这类岩石含有氧化铁矿物。但是没有与周围地区做比较。故选项错误。
C：文章未说它们是因为什么而死亡的。故选项错误。
D：符合文意，正确。

question_stem: The word "advantageous" in the passage is closest in meaning to
choices: tag: A
text: beneficial

tag: B
text: necessary

tag: C
text: remarkable

tag: D
text: common
answer_key: A
explanation: 【题目翻译】段落中的“advantageous”一词最接近于以下哪个选项？
A：有益的
B：必须的 
C：显著的
D：共同的

【判定题型】：题目要求选出与高亮单词意思最接近的选项，故判断本题为词汇题。

【关键词定位】：根据关键词“advantageous”,定位到原句“If there were periods of drought, any adaptations allowing the fish to survive the dry conditions would have been advantageous.”。

【词汇解析】词汇“advantageous”的意思是“有利益的”,带入到原句中，原句的意思是“如果有干旱时期，任何使鱼类在干旱条件下生存的适应都是有利的。”。

【选项分析】
A：有益的。同义替换，正确
B：必须的。不符，错误
C：显著的。不符，错误
D：共同的。不符，错误

question_stem: In paragraph 2, why does the author include the information that mud inside rhipidistian crossopterygian fossils differed in consistency and texture depending on where the mud was located?
choices: tag: A
text: To provide evidence that rhipidistian crossopterygian lived in river channels and lakes on large deltas.

tag: B
text: To identify an effect of the oxidation of iron minerals on the evolution of rhipidistian crossopterygian.

tag: C
text: To help explain why scientists have concluded that rhipidistian crossopterygian probably had lungs.

tag: D
text: To explain why scientists decided to cut cross sections through some fossils of rhipidistian crossopterygian.
answer_key: C
explanation: 【题目翻译】在第2段中，作者为什么要包含这样的信息：泥盆纪扇鳍鱼化石中的泥在稠度和质地上的差异取决于泥的位置？
A：为证明大三角洲上的河道和湖泊中生活着泥盆纪扇鳍鱼提供证据。

B：研究铁矿物氧化对泥盆纪扇鳍鱼进化的影响。

C：为了解释为什么科学家已经得出结论，泥盆纪扇鳍鱼可能有肺。

D：为了解释为什么科学家们决定通过一些泥盆纪扇鳍鱼化石来切割横截面。

【判定题型】：根据题干问法“why …… include”，题目询问“xxxxxx”(文章引用内容)的修辞目的，可以判断本题为修辞目的题。

【关键词定位】通过题目中的关键词 consistency and texture 定位到第二段原句 Cross sections cut through some of the fossils reveal that the mud filling the interior of the carcass differed in consistency and texture depending on its location inside the fish. These differences suggest a sadlike cavity below the front end of the gut that can only be interpreted as a lung. 

【引用内容分析】该定位句意思是一些化石的横截面显示，扇鳍鱼尸体内的泥的稠度和质地根据其在体内位置的不同而不同。为了解释为什么科学家得到泥盆纪扇鳍鱼可能有肺的结论。

【选项分析】
A：不符，错误
B：不符，错误
C：符合文意，正确
D：不符，错误

question_stem: 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.
choices: tag: A
text: Because the lungs of these fish were able to provide only a small amount of oxygen, these fish obtained most of their oxygen through their gills during periods of drought.

tag: B
text: During periods of extended drought, these fish used their lungs to increase their intake of oxygen beyond the levels absorbed by the gills in normal times.

tag: C
text: Although these fish primarily used their gills to obtain oxygen, they used their lungs to obtain oxygen from the air when there was not enough in the water.

tag: D
text: During periods of extended drought, the gills became an auxiliary breathing device and the lungs became the main source of oxygen for these fish.
answer_key: C
explanation: 【题目翻译】下面哪个句子最能表达文章中突出句子的基本信息？不正确的选择会以重要方式改变含义，或者漏掉必要的信息。
A：因为这些鱼的肺只能提供少量氧气，所以在干旱期间，这些鱼通过鳃获得大部分氧气。

B：在长期干旱期间，这些鱼用肺来增加氧气的摄入量，超过正常时期鳃吸收的水平。

C：尽管这些鱼主要是用鳃来获取氧气，但当水中没有足够的氧气时，它们还是用肺从空气中获取氧气。

D：在长期干旱期间，鳃成为辅助呼吸装置，肺成为这些鱼的主要氧气来源。

【判定题型】：根据题目问法，题目要求选择和高亮句意思逻辑都最为接近的句子，故判断本题为句子简化题。

【句子分析】Gills were undoubtedly the main source of oxygen for these fish, but the lungs served as an auxiliary breathing device for gulping air when the water became oxygen depleted, such as during extended periods of drought.关注逻辑词 but。翻译为：对于这些鱼来说，腮毫无疑问是氧气主要来源，但是肺对于呼吸空气来说是辅助呼吸设备，当水中氧气耗尽的时候，特别是在干燥延长的时候。 

【选项分析】
A.错。lungs 和 gills 特征交换，出 most 这样的虚假最高级。 
B.错。in normal times 没有出现 gills 和 lungs 量上的比较。 
C.正确。although=but 逻辑正确，鱼主要靠 gills 获得氧气，当没有足够水的时候，靠 lungs 获得氧气，这句话是文章正确改写。 
D.错。gills 和 lungs 特征交换，出现错误。

question_stem: According to paragraph 3, the structure of the fins of rhipidistian crossopterygian may have allowed these fish to
choices: tag: A
text: reduce the amount of oxygen needed for survival

tag: B
text: develop thick, sturdy bones

tag: C
text: move more efficiently in water

tag: D
text: move short distances over areas that were mostly dry
answer_key: D
explanation: 【题目翻译】根据第3段，泥盆纪扇鳍鱼的鳍的结构可能允许这些鱼
A：减少生存所需的氧气量

B：骨骼粗壮。

C：在水中更有效地移动

D：在大部分干燥的地方短距离移动。

【判定题型】：题目问的是文章中的具体细节信息，故根据题目问法可以判断本题为事实信息题。

【关键词定位】：根据关键词“he structure of the fins”,定位到 Passage 3 第2、3句，原句为“The fins were thick, fleshy, and quite sturdy, with a median axis of bone down the center. They could have been used as feeble locomotor devices on land, perhaps good enough to allow a fish to flop its way from one pool of water that was almost dry to an adjacent pond that had enough water and oxygen for survival. ”，意思是“鱼鳍很厚，肉质，非常结实，中轴骨位于中央。它们可能被用作陆地上微弱的运动装置，也许足够好让鱼从一个几乎干燥的水池中扑通扑通地游到附近一个有足够的水和氧气生存的水池中。”。

【逻辑分析】：结合题目问法和出题句，进行逻辑分析。

【选项分析】
A：文章中：使它可以去到有足够氧气的地方。而不是减少氧气量。故选项错误。
B：没有提到骨骼粗壮。故选项错误。
C：文章中：“扑通扑通地移动”说明移动并不是很有有效。故选项错误。
D：符合文意，正确。

question_stem: The word "adjacent" in the passage is closest in meaning to:
choices: tag: A
text: nearby

tag: B
text: available

tag: C
text: temporary

tag: D
text: fresh
answer_key: A
explanation: 【题目翻译】段落中的“adjacent”一词最接近于：
A 附近的
B 可用的
C 暂时的
D 新鲜的

【判定题型】：题目要求选出与高亮单词意思最接近的选项，故判断本题为词汇题。

【关键词定位】：根据关键词“adjacent”,定位到原句“They could have been used as feeble locomotor devices on land, perhaps good enough to allow a fish to flop its way from one pool of water that was almost dry to an adjacent pond that had enough water and oxygen for survival. ”。

【词汇解析】：词汇“adjacent”的意思是“附近的”,带入到原句中，原句的意思是“它们可能被用作陆地上微弱的运动装置，也许足够好让鱼从一个几乎干燥的水池中扑通扑通地游到附近一个有足够的水和氧气生存的水池中。”。

【选项分析】
A 附近的。同义替换，正确
B 可用的。不符，错误
C 暂时的。不符，错误
D 新鲜的。不符，错误

question_stem: The word “progressively” in the passage is closest in meaning to
choices: tag: A
text: increasingly

tag: B
text: noticeably

tag: C
text: occasionally

tag: D
text: rapidly
answer_key: A
explanation: 【题目翻译】段落中的“progressively”一词最接近于：
A 越来越多地
B 显著地
C 偶尔地
D 迅速地

【判定题型】：题目要求选出与高亮单词意思最接近的选项，故判断本题为词汇题。

【关键词定位】：根据关键词“progressively”,定位到原句“Changes in climate during the Devonian may have had something to do with this if freshwater areas became progressively more restricted. ”。

【词汇解析】：词汇“progressively”的意思是“渐进地”,带入到原句中，原句的意思是“如果淡水区域逐渐受到限制，泥盆纪期间的气候变化可能与此有关。”

【选项分析】
A 越来越多地。同义替换，正确
B 显著地。不符，错误
C 偶尔地。不符，错误
D 迅速地。不符，错误

question_stem: In paragraph 4, why does the author point out that crabs and other arthropods were already living on land when the ancestors of the first tetrapods began living there?
choices: tag: A
text: To account for the presence of dead fish along the edges of ponds and streams during the Devonian.

tag: B
text: To support the claim that climate change caused freshwater habitats to become more restricted during the Devonian.

tag: C
text: To identify a consequence of the emergence of plants into terrestrial habitats near ponds and streams.

tag: D
text: To identify a possible reason for why certain fish gradually became terrestrial organisms.
answer_key: D
explanation: 【题目翻译】在第4段中，作者为什么要指出当最早的四足动物的祖先开始在陆地上生活时，螃蟹和其他节肢动物已经在陆地上生活了？
A：考虑到泥盆纪时期池塘和溪流边上有死鱼。

B：支持气候变化导致泥盆纪期间淡水栖息地变得更加受限的说法。

C：确定植物进入池塘和溪流附近陆地栖息地的后果。

D：找出某些鱼类逐渐成为陆地生物的可能原因。

【判定题型】：根据题干问法“why …… point out ”，题目询问“xxxxxx”(文章引用内容)的修辞目的，可以判断本题为修辞目的题。

【关键词定位】：根据关键词“crabs”,定位到 Passage 4 第1句，原句为“What ecological pressures might have caused fishes to gradually abandon their watery habitat and become increasingly land-dwelling creatures? Changes in… Another impetus... In addition, plants had emerged into terrestrial habitats in areas near streams and ponds, and crabs and other arthropods were also members of this earliest terrestrial community.”。

【引用内容分析】原文 第4段通过一个问句开始，什么生态压力可能促使鱼逐渐抛弃它们的水生环境并逐渐地变成陆生物种的？下面通过三点来对此进行阐述，crabs and other arthropods 就是 in addition 的其中一点来印证的。

【选项分析】
A：文章：并不是要吃死鱼，而是为什么找丰富的蛋白质，所以是要找出某些鱼类逐渐成为陆地生物的可能原因。故选项错误。
B：文章：并未支持某种说法。故选项错误。
C：文章：后果不是重点。故选项错误。
D：选项 D 为了证明为什么某些鱼类逐渐变成陆生生物的一个可能原因,与原文一致。正确。

question_stem: According to paragraph 4, teeth of the earliest tetrapods suggest that these tetrapods
choices: tag: A
text: competed with other animals for protein

tag: B
text: were probably carnivores

tag: C
text: could easily climb out of water

tag: D
text: were able to eat plants
answer_key: B
explanation: 【题目翻译】根据第4段，最早的四足动物的牙齿表明这些四足动物有以下哪些特征？
A：与其他动物争夺蛋白质

B：可能是食肉动物

C：很容易从水里爬出来

D：能吃植物

【判定题型】：题目问的是文章中的具体细节信息，故根据题目问法可以判断本题为事实信息题。

【关键词定位】通过关键词 teeth of the earliest tetrapods 定位到第4段 Evidence from teeth suggests that these earliest tetrapods did not utilize land plants as food; they were presumably carnivorous and had not developed the ability to feed on plants. 

【逻辑分析】早期的 tetrapods 四足动物没有利用陆地植物作为食物，它们大概还是食肉动物并还没有能力发展成靠植物为食。

【选项分析】
A：不符，错误。
B：与原文意思一致，正确。
C：不符，错误。
D：不符，错误。

question_stem: According to paragraph 5, which of the following was true of the first tetrapods?
choices: tag: A
text: They became dependent for food on organisms already living on land.

tag: B
text: They needed to develop new mechanisms for obtaining nutrients.

tag: C
text: They continued to live in close association with aquatic environments.

tag: D
text: They were evolutionarily far removed from their rhipidistian ancestors.
answer_key: C
explanation: 【题目翻译】根据第5段，下列哪一个对第一种四足动物是正确的？
A：它们开始依赖已经在陆地上生存的有机体作为食物。

B：他们需要开发新的获取营养的机制。

C：它们继续与水生环境密切相关。

D：他们在进化上与他们的泥盆纪鱼的祖先相距甚远。

【判定题型】：题目问的是文章中的具体细节信息，故根据题目问法可以判断本题为事实信息题。

【关键词定位】：根据关键词“the first tetrapods”,定位到 Passage 5 第2句，原句为“How did the first tetrapods make the transition to a terrestrial habitat? Like early land plants such as rhyniophytes, they made only a partial transition; they were still quite tied to water. ”，意思是“最初的四足动物是如何过渡到陆地栖息地的？像早期的陆生植物，如流纹植物一样，它们只发生了部分转变；它们仍然与水紧密相连。”。

【逻辑分析】第5段开篇用问句提问早期的 tetrapods 是如何转型到陆生环境的？接着提到像早期的植物，它们只是部分的转型，还是相当依赖于水的。

【选项分析】
A：文章：未提到依赖于陆地上的有机体。故选项错误。
B：文章：未提到开发新的营养机制。故选项错误。
C：文章：它们继续生活在与水密切相关有水的环境里的，选项与原文意思一致。正确。
D：文章：它们和祖先有流通系统，而不是相距甚远。故选项错误。

question_stem: According to paragraph 5, what was the main way that the earliest tetrapods differed from their immediate fish ancestors?
choices: tag: A
text: The tetrapods had a different skeletal structure.

tag: B
text: The tetrapods had more sources of food available.

tag: C
text: The tetrapods had a circulation system.

tag: D
text: The tetrapods could move to new pools of water.
answer_key: A
explanation: 【题目翻译】：根据第5段，最早的四足动物与其直接鱼类祖先的主要方式是什么？
A：四足动物的骨骼结构不同。

B：四足动物有更多的食物来源。

C：四足动物有一个循环系统。

D：四足动物可以移到新的水池里。

【判定题型】：题目问的是文章中的具体细节信息，故根据题目问法可以判断本题为事实信息题。

【关键词定位】：根据关键词“ tetrapods ”,定位到 Passage 5最后一句，原句为“定位句 The principal changes for the earliest tetrapods were in the skeletal system—changes in the bones of the fins, the vertebral column, pelvic girdle, and pectoral girdle. ”，意思是“最早期的四足动物主要进化的是骨骼系统，即鳍骨、脊柱、骨盆、肩胛骨发生变化。”。

【逻辑分析】注意题目问的是 main way 与 principal changes 意思一致，原文最早的 tetrapods 的主要变化是 skeletal system 骨骼结构。

【选项分析】
A：选项中 tetrapods 有不同的骨骼结构与之意思一致。正确。
B：不符，错误。
C：不符，错误。
D：不符，错误。