Passage 3 Two Kinds of Lizards 文章阅读--- 第一步话题及中心思想 Passage 3 Two Kinds of Lizards 本文属动物类话题。 文章话题是：两种蜥蜴的相同点与不同点

文章阅读---第二步跳读，提炼文章中心思想 Paragraph 1 Lizards can be divided into two types according to the way they look for food: sit-and-wait foragers and active foragers. （中心句：Lizards分为2类） Sit-and-wait lizards normally remain in one spot from which they can survey a broad area. These motionless lizards detect the movement of an insect visually and capture it with a quick run from their observation site. Sit-and-wait lizards may be most successful in detecting and capturing relatively large insects like beetles and grasshoppers.（介绍第一种蜥蜴的特点：Sit-and-wait lizards） Active foragers, on the other hand, spend most of their time on the ground surface, moving steadily and poking their heads under fallen leaves and into crevices in the ground. These lizards apparently rely largely on chemical cues to detect insects, and they probably seek out local concentrations of prey such as termites. Active foragers appear to eat more insects than do lizards that are sit-and-wait predators. Thus, the different foraging behaviors of lizards lead to differences in their diets, even when the two kinds of lizards occur in the same habitat. （介绍第二种蜥蜴的特点：Active forager）

B. at an unvarying rate C. cautiously D. without making noise A. 题型解答--词汇题 1.The word steadily in the passage is closest in meaning to B. at an unvarying rate C. cautiously D. without making noise A. slowly Steadily 稳定的，所以答案为B

B. dense groupings C. hidden traces D. shelters A. varieties 题型解答--词汇题 2. The word concentrations in the passage is closest in meaning to B. dense groupings C. hidden traces D. shelters A. varieties Concentrations 集中，集合， 所以答案为B

题型解答—否定事实信息题 3. According to paragraph 1, sit-and-wait foragers and active foragers are different in all of the following EXCEPT A. the methods that they primarily use to detect insects B. the number of insects they typically eat C. the habitats in which they can be found（与第一段最后一句信息不符合） D. the amount of time they spend moving 所以答案为C.

题型解答—事实信息题 4. According to paragraph 1, compared to the insects typically consumed by sit-and-wait lizards, insects typically consumed by active lizards A. move more quickly B. are generally found in smaller groups C. are often hidden from view D. spend more time on the surface of the ground 根据题干定位到“Active foragers, on the other hand, spend most of their time on the ground surface, moving steadily and poking their heads under fallen leaves and into crevices in the ground.”可以得出答案为C.

文章阅读---第二步跳读，提炼文章中心思想 Paragraph 2 ①The different foraging modes also have different consequences for lizards regarding their exposure to predators. (中心句：蜥蜴的捕食模式的不同) ②A lizard that spends 99 percent of its time resting motionless is relatively inconspicuous, whereas a lizard that spends most of its time moving is easily seen. （递进展开） ③Sit-and-wait lizards are probably most likely to be discovered and captured by predators that are active searchers, whereas widely foraging lizards are likely to be caught by sit-and-wait predators.（递进展开，2种蜥蜴被捕食的不同方式） ④Because of this difference, foraging modes may alternate at successive levels in the food chain: insects that move about may be captured by lizards that are sit-and-wait foragers, and those lizards may be eaten by active predators, whereas insects that are sedentary are more likely to be discovered by lizards that are active foragers, and those lizards may be caught by sit-and-wait predators.（递进展开：2种蜥蜴与predators的关系）

题型解答—修辞目的题 5.In paragraph 2, why does the author contrast the visibility of lizards that remain motionless most of the time with the visibility of lizards that move most of the time A. To show that it is possible for lizards to alternate their foraging modes at successive levels in the food chain B. To suggest that sit-and-wait lizards are more likely than active lizards to be attacked by predators C. To explain why sit-and-wait lizards are more successful than active lizards at preying on insects D. To explain how a lizard's foraging strategy affects the type of predator likely to attack it 根据题干定位到第2，3，4句，第2句和第3句理论阐述花费99%的时间在移动，第4句总结这些差异是为了什么原因，所以正确答案为A.

文章阅读---第二步跳读，提炼文章中心思想 Paragraph 3 ①The body forms of sit-and-wait foragers may reflect selective pressures different from those that act on active foragers.（中心句：2种蜥蜴的body form的区别）②Sit-and-wait lizards are often stout bodied, short tailed, and colored to match their background.③Many of these species have patterns of different-colored blotches that probably obscure the outlines of the lizard's body as it rests motionless on a rock or a tree trunk.（2-3句递进展开，Sit-and-wait lizards的body form的特点）④Active foragers are usually slim and elongated with long tails, and they often have patterns of stripes that may produce optical illusions as they move. （（递进展开，Active foragers的body form的特点） ⑤However, one predator-avoidance mechanism, the ability to break off their tails when they are seized by predators, does not differ among lizards with different foraging modes.（总结：2种蜥蜴的共同点）

D. require 要求 Reflect 反映表达 A. indicate 表明，指示 B. create 创造 C. resist 抵抗 题型解答--词汇题 6.The word reflect in the passage is closest in meaning to D. require 要求 Reflect 反映表达 A. indicate 表明，指示 B. create 创造 C. resist 抵抗 所以答案为A

D. expand 扩张 A. change 改变 B. hide 隐藏 C. fill 装满 题型解答--词汇题 7. The word obscure in the passage is closest in meaning to D. expand 扩张 A. change 改变 B. hide 隐藏 C. fill 装满 Obscure 模糊的，隐藏的，所以答案为B

题型解答—修辞目的题 8. Paragraph 3 supports which of the following ideas about active-forager lizards A. They are less likely to break off their tails when seized by predators than sit-and-wait lizards are. B. They tend to vary widely in their individual colors. C. They lack well-developed mechanisms for avoiding predators. D. They may be easier to identify when they are not moving than when they are moving. 第3段主要介绍2种蜥蜴的body form的不同，所以答案为D.

文章阅读---第二步跳读，提炼文章中心思想 Paragraph 4 ①What physiological characteristics are necessary to support different foraging modes？（中心句：捕食模式与身体特征的关系？）②The energy requirements of a quick motion that lasts for only a second or two are quite different from those of locomotion that is sustained nearly continuously for several hours.（递进展开：quick motion与 locomotion需要能量的不同）③Sit-and-wait lizards and active foragers differ in their relative emphasis on the two ways that most animals use adenosine triphosphate (ATP)（三磷酸腺苷） a molecule that transports energy within cells for activity and in how long that activity can be sustained. (2种蜥蜴身体能量变化的不同) ④Sit-and-wait lizards move in brief spurts, and they rely largely on anaerobic metabolism（厌氧代谢） to sustain their movements, namely the kind of metabolism that does not use oxygen.（递进展开：Sit-and-wait lizards 移动时用的是anaerobic metabolism）⑥Anaerobic metabolism uses glycogen stored in the muscles and produces lactic acid as its end product. ⑦It is a way to synthesize ATP quickly (because the glycogen is already in the muscles), but it is not good for sustained activity because the glycogen is quickly exhausted and lactic acid inhibits cellular metabolism. （递进展开：Anaerobic metabolism的原理）

文章阅读---第二步跳读，提炼文章中心思想 Paragraph 4－2 ⑧Lizards that rely on anaerobic metabolism can make brief sprints but become exhausted when they are forced to run continuously.（递进展开：Lizards主要依靠anaerobic metabolism） ⑨In contrast, aerobic metabolism uses glucose that is carried to the muscles by the circulatory system, and it produces carbon dioxide and water as end products.⑩Aerobic exercise can continue for long periods because the circulatory system brings more glucose and carries carbon dioxide away. （（对比分类：aerobic metabolis的运用原理）As a result, active foragers can sustain activity for long periods without exhaustion. Active species of lizards have larger hearts and more red blood cells in their blood than do sit-and-wait species. As a result, each beat of the heart pumps more blood, and that blood carries more oxygen to the tissues of an active species than a sit-and-wait species.（（递进展开：active foragers所使用的身体原理）

题型解答—事实信息题 9. According to paragraph 4, compared with active lizards, the movements of sit-and-wait lizards are A. more sudden B. more sustained C. more predictable D. more frequent 根据题干定位到“④Sit-and-wait lizards move in brief spurts, and they rely largely on anaerobic metabolism to sustain their movements, namely the kind of metabolism that does not use oxygen.” ⑥Anaerobic metabolism uses glycogen stored in the muscles and produces lactic acid as its end product. ⑦It is a way to synthesize ATP quickly (because the glycogen is already in the muscles), but it is not good for sustained activity because the glycogen is quickly exhausted and lactic acid inhibits cellular metabolism.可以得出答案为A

题型解答—否定事实信息题 10. According to paragraph 4, all of the following are true about anaerobic metabolism in lizards EXCEPT: A. It uses the glycogen in the muscles of lizards. B. It produces lactic acid that interferes with metabolism within the cells of lizards. C. It allows lizards to maintain their foraging activity over a long period of time. D. It allows lizards to run fast for short periods of time. 根据题干定位到“⑥Anaerobic metabolism uses glycogen stored in the muscles and produces lactic acid as its end product. ⑦It is a way to synthesize ATP quickly (because the glycogen is already in the muscles), but it is not good for sustained activity because the glycogen is quickly exhausted and lactic acid inhibits cellular metabolism.”可以得出答案为C.

题型解答—推断题 11. Which of the following can be inferred from paragraph 4 about sit-and-wait lizards A. They have less glycogen than active-forager lizards.（应该是多余） B. They have highly variable heart rates.（对象错了，应该是active lizards highly variable heart rates.） C. They have metabolic systems that do not depend on the efficient removal of carbon dioxide. D. They synthesize adenosine triphosphate continuously.（应该是quickly，不是continuously） 所以得出答案为C

题型解答—事实信息题 12. According to paragraph 4, how are active-foraging lizards and sit-and-wait lizards different from each other A. Sit-and-wait lizards tend to have more red blood cells in their blood than active-foraging lizards do.（内容说反了） B. Active-foraging lizards' blood carries less oxygen to the tissues than sit-and-wait foraging lizards' blood does.（内容说反了） C. Sit-and-wait lizards carry out cellular metabolism more efficiently than active-foraging lizards do.（内容错误） D. Active-foraging lizards tend to have larger hearts than sit-and-wait lizards do. 所以得出答案为D.

题型解答—句子插入题 13. Look at the four squares that indicate where the following sentence could be added to the passage. Such visual effects make it harder for predators to catch these moving targets. Where would the sentence best fit? Click on a square to add the sentence to the passage. 插入句“Such visual effects make it harder for predators to catch these moving targets.”可以得出前句是跟visual effects有关的， 同时会与“predators”“moving targets”有关系，所以得出答案为C.

题型解答—总结题 14. Drag your choices to the spaces where they belong. To review the passage, click on View Text. Answer Choices A. Sit-and-wait lizards use brief spurts of energy to forage, while the movements of active lizards are more sustained.(内容正确，对应原文第4段) B. Lizards that are active foragers are able to detect insects even when those insects are stationary, but sit-and-wait lizards are able to detect only moving insects.（内容错误，不是are able to detect only moving insects） C. Sit-and-wait lizards tend to have predators that are active, while active lizards tend to have sit-and-wait predators.（内容错误，与原文第3段信息不符合） D. Sit-and-wait lizards have less need for bodies that match their environment than active lizards do because of the ease with which they can break off their tails to escape from predators.（内容正确） E. The body forms and metabolic functions of the two types of lizards differ in ways that support the requirements of their different foraging behaviors.（内容正确） F. Sit-and-wait lizards derive energy for movement from anaerobic metabolism alone, while active lizards rely almost equally on aerobic and anaerobic metabolisms.（内容错误，active lizards rely almost equally on aerobic and anaerobic metabolisms不对） 所以答案为ADE.

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