下载文档原格式
老托福阅读真题及答案:passage11为了帮助大家备考托福阅读，提高成绩，下面小编给大家带来老托福阅读真题及答案:passage 11，希望大家喜欢！老托福阅读真题及答案:passage 11Plants are subject to attack and infection by a remarkable variety of symbiotic species and have evolved a diverse array of mechanisms designed to frustrate the potential colonists. These can be divided into preformed or passive defense mechanisms and inducible or active systems. Passive plant defense comprises physical and chemical barriers that prevent entry of pathogens, such as bacteria, or render tissues unpalatable or toxic to the invader. The external surfaces of plants, in addition to being covered by an epidermis and a waxy cuticle, often carry spiky hairs known as trichomes, which either prevent feeding by insects or may even puncture and kill insect larvae. Other trichomes are sticky and glandular and effectively trap and immobilize insects.If the physical barriers of the plant are breached, then preformed chemicals may inhibit or kill the intruder, and plant tissues contain a diverse array of toxic or potentially toxic substances, such as resins, tannins, glycosides, and alkaloids, many of which are highly effective deterrents to insects that feed on plants. The success of the Colorado beetle in infesting potatoes, for example, seems to be correlated with its high tolerance to alkaloids that normally repel potential pests. Other possible chemical defenses, while not directly toxic to the parasite, may inhibit some essential step in the establishment of a parasitic relationship. For example, glycoproteins in plant cell walls may inactivate enzymes that degrade cell walls. These enzymes are often produced by bacteria and fungi.Active plant defense mechanisms are comparable to the immune system of vertebrate animals, although the cellular and molecular bases are fundamentally different. Both, however, are triggered in reaction to intrusion, implying that the host has some means of recognizing the presence of a foreign organism. The most dramatic example of an inducible plant defense reaction is the hypersensitive response. In the hypersensitive response, cells undergo rapid necrosis — that is, they become diseased and die —after being penetrated by a parasite; the parasite itself subsequently ceases to grow and is therefore restricted to one or a few cells around the entry site. Several theories have been put forward to explain the basis of hypersensitive resistance.1. What does the passage mainly discuss?(A) The success of parasites in resisting plant defense mechanisms(B) Theories on active plant defense mechanisms(C) How plant defense mechanisms function(D) How the immune system of animals and the defense mechanisms of plants differ2. The phrase "subject to" in line 1 is closest in meaning to(A) susceptible to(B) classified by(C) attractive to(D) strengthened by3. The word "puncture" in line 8 is closest in meaning to(A) pierce(B) pinch(C) surround(D) cover .4. The word "which" in line 12 refers to(A) tissues(B) substances(C) barriers(D) insects5. Which of the following substances does the author mention as NOT necessarily being toxic to the Colorado beetle?(A) resins(B) tannins(C) glycosides(D) alkaloids6. Why does the author mention "glycoproteins" in line 17?(A) to compare plant defense mechanisms to the immune system of animals(B) to introduce the discussion of active defense mechanisms in plants(C) to illustrate how chemicals function in plant defense(D) to emphasize the importance of physical barriers in plant defense7. The word "dramatic" in line 23 could best be replaced by(A) striking(B) accurate(C) consistent(D) appealing8. Where in the passage does the author describe an active plant-defense reaction?(A) Lines 1-3(B) Lines 4-6(C) Lines 13-15(D) Lines 24-279. The passage most probably continues with a discussion of theories on(A) the basis of passive plant defense(B) how chemicals inhibit a parasitic relationship.(C) how plants produce toxic chemicals(D) the principles of the hypersensitive response.正确答案:CAABD CADD托福阅读易错词汇的整理1) quite 相当 quiet 安静地2) affect v 影响, 假装 effect n 结果, 影响3) adapt 适应 adopt 采用 adept 内行4) angel 天使 angle 角度5) dairy 牛奶厂 diary 日记6) contend 奋斗, 斗争content 内容, 满足的context 上下文contest 竞争, 比赛7) principal 校长, 主要的 principle 原则8) implicit 含蓄的 explicit 明白的9) dessert 甜食 desert 沙漠 v 放弃 dissert 写论文10) pat 轻拍 tap 轻打 slap 掌击 rap 敲，打11) decent 正经的 descent n 向下, 血统 descend v 向下12) sweet 甜的 sweat 汗水13) later 后来 latter 后者 latest 最近的 lately adv 最近14) costume 服装 custom 习惯15) extensive 广泛的 intensive 深刻的16) aural 耳的 oral 口头的17) abroad 国外 aboard 上(船，飞机)18) altar 祭坛 alter 改变19) assent 同意 ascent 上升 accent 口音20) champion 冠军 champagne 香槟酒 campaign 战役21) baron 男爵 barren 不毛之地的 barn 古仓22) beam 梁，光束 bean 豆 been have 过去式23) precede 领先 proceed 进行，继续24) pray 祈祷 prey 猎物25) chicken 鸡 kitchen 厨房26) monkey 猴子 donkey 驴27) chore 家务活 chord 和弦 cord 细绳28) cite 引用 site 场所 sight 视觉29) clash (金属)幢击声 crash 碰幢，坠落 crush 压坏30) compliment 赞美 complement 附加物31) confirm 确认 conform 使顺从32) contact 接触 contract 合同 contrast 对照33) council 议会 counsel 忠告 consul 领事34) crow 乌鸦 crown 王冠 clown 小丑 cow 牛35) dose 一剂药 doze 打盹36) drawn draw 过去分词 drown 溺水托福阅读学术词汇的解析什么是学术词汇在托福阅读的课堂上，经常有学生对繁杂的学术词汇头疼不已。
托福阅读辅导:老托福阅读真题及答案passage30为了关怀大家备考托福阅读，练习更多阅读题目。
提高阅读水平，下面我给大家带来托福阅读辅导:老托福阅读真题及答案PASSAGE30，希望对大家有所关怀!老托福阅读文本passage30Butterflies are among the most extensively studied insects — it is estimated that 90 percent of the worlds species have scientific names. As a consequence, they are perhaps the best group of insects for examining patterns of terrestrial biotic diversity and distribution. Butterflies also have a favorable image with the general public. Hence, they are an excellent group for communicating information on science and conservation issues such as diversity.Perhaps the aspect of butterfly diversity that has received the most attention over the past century is the striking difference in species richness between tropical and temperate regions. For example, in 1875 one biologist pointed out the diversityof butterflies in the Amazon when he mentioned that about 700 species were found within an hours walk, whereas the total number found on the British islands did not exceed 66, and the whole of Europe supported only 321. This early comparison of tropical and temperate butterfly richness has been well confirmed.A general theory of diversity would have to predict not only this difference between temperate and tropical zones, but also patterns within each region, and how these patterns vary among different animal and plant groups. However, for butterflies, variation of species richness within temperate or tropical regions, rather man between them, is poorly understood. Indeed, comparisons of numbers of species among the Amazon basin, tropical Asia, and Africa are still mostly personal communication citations, even for vertebrates. In other words, unlike comparison between temperate and tropical areas, these patterns are still in the documentation phase.In documenting geographical variation in butterfly diversity, some arbitrary, practical decisions are made. Diversity, number of species, and species richness are used synonymously; little is known about the evenness of butterfly distribution. The New World butterflies make up the preponderance of examples because they are the most familiar species. It is hoped that by focusing on them, the errors generated by imperfect and incomplete taxonomy will be minimized.老托福阅读题目passage301. Which aspect of butterflies does the passage mainly discuss?(A) Their physical characteristics(B) Their names(C) Their adaptation to different habitats(D) Their variety2. The word consequence in line 2 is closest in meaning to(A) result(B) explanation(C) analysis(D) requirement3. Butterflies are a good example for communicating information about conservation issues because they(A) are simple in structure(B) are viewed positively by people(C) have been given scientific names(D) are found mainly in temperate climates4. The word striking in line 8 is closest in meaning to(A) physical(B) confusing(C) noticeable(D) successful5. The word exceed in line 11 is closest in meaning to(A) locate(B) allow(C) go beyond(D) come close to6. All of the following are mentioned as being important parts of a general theory of diversity EXCEPT(A) differences between temperate and tropical zones(B) patterns of distribution of species in each region(C) migration among temperate and tropical zones(D) variation of patterns of distribution of species among different animals and plants7. The author mentions tropical Asia in lines 19 as an example of a location where(A) butterfly behavior varies with climate(B) a general theory of butterfly diversity has not yet been firmly established(C) butterflies are affected by human populations(D) documenting plant species is more difficult than documenting butterfly species8. Which of the following is NOT well understood by biologists?(A) European butterfly habitats(B) Differences in species richness between temperate and tropical regions(C) Differences in species richness within a temperate or a tropical region(D) Comparisons of behavior patterns of butterflies and certain animal groups9. The word generated in line 26 is closest in meaning to(A) requested(B) caused(C) assisted(D) estimated老托福〔阅读答案〕passage30DABCC CBCB4个Tip攻克托福阅读词汇题托福中的词汇题是不是让同学们的都很手足无措，可能新手考生还不太明白什么是阅读中的词汇题，即选择4个选项中和原文某一词汇意义表达相同的选项，题目基本都为The word X in the passage is closest in meaning to ......为什么很多考生会对词汇题束手无措?一方面是因为考生的词汇量达不到，OG中词汇题的解释里有一句话，there is no list of words that must be tested. 这句话就告知考生死了那条心去背所谓的大纲词汇，因为没有大纲，而考试中要考查到的单词可能是来自牛津字典或朗文字典中的任何一个单词，范围大的离谱;而另一方面则是因为有的考生没有学会从上下文或者从语法结构去猜测词义。
托福阅读经典加试：沙漠的形成托福阅读加试分为经典加试和非经典加试，一般情况下考生遇到的情况都是经典加试，即所加试的题目都是固定的几篇。
这里小编为就为大家整理了阅读经典加试：沙漠的形成分享给大家，希望对大家托福备考有帮助。
托福阅读经典加试：沙漠的形成托福阅读经典加试题：沙漠的形成举了Sahara，说那里以前也不是沙漠，地下有河流的痕迹。
有一段说了形成的原因，提到温差巨大导致岩石破裂(是个考点)。
还有一段提到了Sahara 反反复复的过程(考点)。
最后还提到了研究地球的沙漠和究其他行星的关系，(也是一道题)托福阅读经典加试题：沙滩的形成包括形成的条件，有一段说beach 的构成(composition)和size，beach 的底部的组成。
有的 beach 底部是珊瑚，有的是石头，有的是沙子，但像加州海岸会随季节变化而变化。
另一段讲好沙滩的形成需要smooth 的地理条件，美国东海岸有的地方外围有什么保护，所以里面的beach还不错。
并拿欧洲作了对比。
最后几段还提到了水对beach 形成的作用。
托福阅读背景知识之始祖鸟古生物学是生命科学和地球科学汇合的交叉科学。
既是生命科学中唯.具有历史科学性质的时间尺度的一个独特分支，研究生命起源、发展历史、生物宏观进化等历史生物学的重要基础和组成部分：又是地球科学的一个分支，研究保存在地层中的生物遗体、遗迹、化石，用以确定地层的顺序、时代，了解古生物的发展历史，推断地质史上水陆分布、气候变迁和沉积矿产形成与分布的规律。
托福阅读机经要点：(1)始祖鸟的化石保存得十分完整。
(2)动物学家认为始祖鸟属于鸟类。
(3)古生物学家认为始祖鸟属于恐龙。
(4)教授更赞成古生物学家的观点。
背景拓展：(一)始祖鸟化石始祖鸟化石都是在德国的巴伐利亚州的石灰岩层中发现的，距现在已有1.5亿年了，这些化石被证明为始祖鸟。
这些化石上有清晰的羽毛印痕，而且分为初级和次级飞羽，还有尾羽。
它的前肢退化成飞行的翅膀，后足。
托福阅读：2011.1.8托福阅读考试机经回顾托福机经阅读:第一篇：关于"棘冠海星"(crown of thorns Starfish)和Coral Reef 的东西这个托福机经阅读，我是因为之前看过一个纪录片就见过这个物种，所以一看到照片就知道这种starfish是吃coral reef的而且，在Grate Coral Reef问题很严重，其中主要因素是人为因素。
但是，背景知识只能帮助我们理解文章，不能完全依赖。
好像讲了这个食物链的问题，海星吃珊瑚，然后好像那种珊瑚长得太多又会影响到别的海藻或者什么东西的生长，然后就说有些时候由于storm的原因珊瑚少了，然后。
好像这样。
有点难没怎么看明白第二篇：关于莫斯科的确定和发展个人回忆：第一段：由来第二段：地理位置、地理学家的猜测第三段：好像在前面还讲了一下关于内陆地区可以抵御invator,以K城市作为反例水路交通剩下的就记不清楚了....说它第一位置超级好是一个三条路会和的地方，所以有很多人迁徙到这里就不再往北边还不是哪个方向走了，然后说它的位置是central，然后周围有N条河(有地图)，这个位置可以水路做生意然后还可以防御进攻总之就是非常好第三篇：森林生态环境的垂直分层现象其实个人认为跟TPO中的一篇Long Standing Ecosystem很像，相关词汇也有涉及文章中主要提到了3种程度破坏：1、自然破坏，例如地震、火山等(对于soil的破坏，长时间才能恢复)2、XX破坏，主要是不破坏soil所以能够在5~10回复(数字仅供参考。
)3、第三种破坏好像是人为性破坏，在文章末尾，记不太清楚了。
这个好难。
生词很多第四篇文章：关于telephone and telegram在美国和在欧洲的发展文章细节不记得了，大致内容：美国比较自由，私人控股、国家调控;欧洲好像是归类到邮政系统，阻碍发展。
而且文章提到了"维多利亚 Internet"并有考题出现。
学生名字：贺泽华做题日期：7/12/2015做题耗时：19min篇章套数：TPO11（1）错第____6、11、13________题共____14___ 题，错__3___道。
问题总览：写出错题题型、错题原因、相应题型答题步骤1.第6题，错选D。
修辞目的题。
向前找论点时理解错误。
答题步骤：读题干，读懂原段中信息所在句，找论点（先往前2.第11题，错选A。
词汇题。
看太快，将imagine看为image（图像）。
3.第13题，错选C。
插句题。
句意上成立，但没有表现出“in fact”的转折关系。
答题步骤：读懂插入句，判断（指代关系、逻辑、总分），读原文（从第一黑框前一句到最后黑框后一句）段落大意：1.古埃及艺术创作的原因和意义2.古埃及雕塑和建筑的几何意义3.雕塑的材料和其作用4.雕塑在生活中的用处生词：Squat v.蹲n.蹲坐Pegged v.（用钉子）固定学生名字：贺泽华做题日期：7/12/2015做题耗时：16min篇章套数：TPO11（2）错第____3、6、14________题共____14___ 题，错__3___道。
问题总览：写出错题题型、错题原因、相应题型答题步骤1.第3题，错选B。
复述题。
B项没有讲关于有云时的情况。
答题步骤：精读原句、找出主干，读选项，看选项是否符合原句主干意思，检查选项（修饰的正确性，宁缺毋滥）句子翻译：他于是将星椋鸟关在笼子里做实验，然后发现了它们飞行的方向。
事实上，它们有一定的迁移方向，除了天空都是云的时候，因为这个时候会使它们骚动不安，活动就没有了清楚的方向。
2.第6题，错选A。
细节题。
A选项在文中有对应，但是与问题的题干无关。
答题步骤：看题干，在原文定位，读一片信息（上下文），找选项（在原文中有对应并且符合题干）3.第14题，错选ACE，归总题。
E选项在文中没有说，属于自己yy（忘了怎么yy出来的）。
答题步骤：读题干，看全文，选出可以概括段落大意的选项，且要与文意符合，不能选细节。
老托福阅读试题及答案：PASSAGE16老托福阅读试题及答案： 16The first flying vertebrates were true reptiles in which one of the fingers of the front limbs became very elongated, providing support for a flap of stretched skin that served as a wing. These were the pterosaurs, literally the "winged lizards." The earliest pterosaurs arose near the end of the Triassic period of the Mesozoic Era, some 70 million years before the first known fossils of true birds occur, and they presumably dominated the skies until they were eventually displaced by birds. Like the dinosaurs, some the pterosaurs became gigantic; the largest fossil discovered is of an individual that had a wingspan of 50 feet or more, larger than many airplanes. These flying reptiles had large, tooth-filled jaws, but their bodies were small and probably without the necessary powerful muscles for sustained wing movement. They must have been e某pert gliders, not skillful fliers, relying on wind power for their locomotion.Birds, despite sharing common reptilian ancestors with pterosaurs, evolved quite separately and have been much more successful in their dominance of the air. They are an e某ample of a common theme in evolution, the more or less parallel development of different types of body structure and function for the same reason —in this case, for flight. Although the fossil record, as always, is not complete enough to determine definitively the evolutionary lineage of the birds or in as much detail as one would like, it is better in this case than for many other animal groups. That is because of the unusual preservation in a limestone quarry in southern Germany of Archaeoptery某, a fossil that many have called the linkbetween dinosaurs and birds. Indeed, had it not been for the superb preservation of these fossils, they might well have been classified as dinosaurs. They have the skull and teeth of a reptile as well as a bony tail, but in the line-grained limestone in which these fossils occur there are delicate impressions of feathers and fine details of bone structure that make it clear that Archaeoptery某 was a bird.All birds living today, from the great condors of the Andes to the tiniest wrens, trace their origin back to the Mesozoic dinosaurs.1. What does the passage mainly discuss?(A) Characteristics of pterosaur wings(B) The discovery of fossil remains of Archaeoptery某(C) Reasons for the e某tinction of early flying vertebrates(D) The development of flight in reptiles and birds2. Which of the following is true of early reptile wings?(A) They evolved from strong limb muscles.(B) They consisted of an e某tension of skin.(C) They connected the front and back limbs.(D) They required fingers of equal length.3. The word "literally" in line 3 is closest in meaning to(A) creating(B) meaning(C) related to(D) simplified4. It can be inferred from the passage that birds were probably dominant in the skies(A) in the early Triassic period(B) before the appearance of pterosaurs(C) after the decline of pterosaurs(D) before dinosaurs could be found on land.5. The author mentions airplanes in line 8 in order to(A) illustrate the size of wingspans in some pterosaurs(B) compare the energy needs of dinosaurs with those of modern machines(C) demonstrate the differences between mechanized flight and animal flight(D) establish the practical applications of the study of fossils6. The word "They" in line 10 refers to(A) powerful muscles(B) bodies(C) jaws(D) flying reptiles7. According to the passage , pterosaurs were probably "not skillful fliers" (lines 10-11) because(A) of their limited wingspan(B) of their disproportionately large bodies(C) they lacked muscles needed for e某tended flight(D) climate conditions of the time provided insufficient wind power8. In paragraph 2, the author discusses the development of flight in birds as resulting from(A) a similarity in body structure to pterosaurs(B) an evolution from pterosaurs(C) the dominance of birds and pterosaurs over land animals(D) a separate but parallel development process to that of pterosaurs9. The word "classified" in line 21 is closest in meaning to(A) perfected(B) replaced(C) categorized(D) protected10. Which of the following helped researchers determine that Archaeoptery某 was not a dinosaur?(A) Its tail(B) Its teeth(C) The shape of its skull(D) Details of its bone structure11. What is the significance of the discovery that was made in southern Germany?(A) It is thought to demonstrate that birds evolved from dinosaurs.(B) It is proof that the climate and soils of Europe have changed over time.(C) It suggests that dinosaurs were dominant in areas rich in limestone.(D) It supports the theory that Archaeoptery某 was apowerful dinosaur.正确答案：DBBCA DCDCDA托福阅读的实用技巧整理首先，无论什么技巧都必须要有基本的单词量做基础。
2019托福阅读经典加试题目及答案：鸟鸣有些同学担心考托福阅读的时候遇到加试的情况，想要找一些习题热身，下面小编给大家带来2019托福阅读经典加试题目及答案：鸟鸣，望喜欢~托福阅读真题之经典加试题目及答案：鸟鸣版本一：本文主要讨论鸟叫这种本领究竟是先天遗传的还是后天习得的，并为此做了三个实验，得出了不同的结论。
1. 概述：虽然鸟类都会唱歌，但它们唱歌的旋律、调调是各有差异的。
为了研究它们唱歌的技能是a先天遗传(基因)?b还是后天习得(外界因素)的?researchers 做了很多实验。
2. 试验一中研究人员如何对待小chaffinch?Researchers 首先把刚出生的一只小chaffinch 带离_，放在另外一个地方单独养，与其他大chaffinch 隔离isolate，不让它听到大鸟唱歌song。
3. 试验一的结果如何?结果显示该chaffinch 还是会唱这种歌，只是调子有方言(variation)、很简单、不连续(disconnected)。
这就证明了chaffinch 先天就有唱歌的本领的。
4. 试验二中white necked crow是否被隔离?Researchers 首先把刚出生的一只小white necked crow与其它大鸟隔离，不让它听到大鸟的歌。
5. White necked crow学习唱歌的过程?在刚开始的3 个月，还没有形成自己的歌声前，给小鸟听其它鸟唱歌的磁带recording。
它很快就学会了recording 里的鸟的叫声(dialect)。
6. 试验二的结果是?White necked crow的dialect 不是由基因决定，而是与环境有很大关系。
研究还发现4 个月以后，它都只会唱自己的调调，再给它听别的recording，它也学不会了。
说明后天学习也有时间限制.7. 词汇：unreceptive无法接受的8. 试验三的内容?另一种鸟，F 开头的。
说这种鸟如果不让它们听到自己的声音，它们就只能形成破碎的音节而已，连不成歌。
[导读]托福阅读加试答案：birdsong©⽆忧考⽹编辑为准备参加托福考试的考⽣们提供了"托福阅读加试答案：birdsong"，希望对⼤家有所帮助。
托福阅读加试答案：birdsongbird song 鸟类鸣唱：虽然鸟类都会唱歌，但它们唱歌的旋律、调调是各有差异的。
为了研究它们唱歌的技能是先天遗传（基因）的还是后天习得（外界因素）的，researchers 做了很多实验。
Chaffinch 和北美的white X crow （X可能=necked，winged，billed 等）的幼鸟是如何学会唱歌的。
试验⼀、Researchers ⾸先把刚出⽣的⼀只⼩chaffinch 带离鸟巢，放在另外⼀个地⽅单独养，与其他⼤chaffinch 隔离isolate，不让它听到⼤鸟唱歌song。
在三个⽉以后，到雄性该求爱时放回⾃然，听它的song 是怎样的。
结果显⽰该chaffinch 还是会唱这种歌，只是调⼦有⽅⾔variation、很简单、不连续disconnected。
这就证明了chaffinch 先天就有唱歌的本领的。
试验⼆、Researchers ⾸先把刚出⽣的⼀只⼩white X crow/sparrow 带离鸟巢，放在另外⼀个地⽅单独养，与其它⼤white X crow 隔离，不让它听到⼤鸟的歌。
在刚开始的3 个⽉，还没有形成⾃⼰的歌声前，给⼩鸟听其它鸟唱歌的磁带recording。
它很快就学会了recording ⾥的鸟的叫声（dialect），它的调⼦很快就和那些鸟的调⼦⼀样了。
此研究显⽰：它的dialect 不是由基因决定，⽽是与环境有很⼤关系。
研究还发现4个⽉以后，它都只会唱⾃⼰的调调，再给它听别的recording，它也学不会了unreceptive(考了这个词的意思)。
说明后天学习也有时间限制。
试验三、另⼀种鸟，F 开头的。
说这种鸟如果不让它们听到⾃⼰的声⾳，它们就只能形成破碎的⾳节⽽已，连不成歌。
智课网TOEFL备考资料托福阅读机经：不会飞行的鸟类摘要：托福阅读机经：不会飞行的鸟类.以前，存在没有翅膀的鸟。
因为它们生活在岛屿上，没有天敌。
这种鸟翅膀肌肉不发达是因为发展翅肌的能量还不如自己保存体力。
又说到后来它们因为环境等因素不得不进化，而没有进化的鸟就因为人类入侵而灭绝了。
不会飞的鸟是指已失去飞行能力的鸟类，取而代之的是奔跑及游泳的能力。
虽然如此，但普遍相信它们都是由懂得飞行的共同祖先进化而来。
现存约有40种不会飞的鸟类，包括企鹅、鸵鸟及鹬鸵(奇异鸟)等广为人知的物种，及部分属于其他目的物种。
除了诸如鸵鸟等大型的不会飞的鸟仍拥有强而有力的爪去对抗猎食者之外，大部分不会飞的鸟所面对的均为没有太多捕猎者的环境、或是隔绝性的海岛，花费极大气力的飞行并不符合效益，因此它们的进化倾向失去这种能力。
相比起其他地区，新西兰有较多的不会飞的鸟类，如奇异鸟、企鹅及南秧鸡等。
其中一个原因是在人类首次踏足这个土地上时(约1000年前)，岛上并没有地栖形的捕猎者，它们最大的敌人反而是大型的猛禽——飞行并不是逃避敌人的有效方法。
不会飞的鸟类在面对人类所造成的威胁时冲击较大，因此它们面临灭绝的机会也较高;幸运的是它们也较易被圈养保护，简单的栏杆已是有效的工具。
人类很早就懂得牧养鸵鸟以取得其羽毛，现在的规模更大，以取得其肉作食及皮作为皮革制品。
【英文题源】Flightless birds are birds which lack the ability to fly, relying instead on their ability to run or swim. They are thought to haveevolved from flying ancestors. There are about forty species in existence today, the best known being the ostrich, emu, cassowary, rhea, kiwi, and penguin. It is believed by somecitation needed that most flightless birds evolved in the absence of predators on islands, and lost the power of flight because they had few enemies — although this is likely not the case for the ratites (the ostrich, emu and cassowary), as all have claws on their feet to use as a weapon against predators.Two key differences between flying and flightless birds are the smaller wing bones of flightless birdsand the absent (or greatly reduced) keel on their breastbone. The keel anchors muscles needed for wing movement. Flightless birds also have more feathers than flying birds.There are at least another two possibilities as to why flightless birds such as ostriches and emus have wings, either.The wings are indeed “useless” and derivedfrom birds that once could fly. This is possible in the creationist model. Loss of features is relatively easy by natural processes, whereas acquisition of new characters, requiring specific new DNA information, is impossible. Loss of wings most probably occurred in a beetle species that colonized a windy island. Again, this is a loss of genetic information, so it is not evidence for microbe-to-man evolution, which requires masses of new genetic information.Some possible functions, depending on the species of flightless bird, are: balance while running, cooling in hot weather, warmth in cold weather, protection of the ribcage during falls, mating rituals, scaring predators (emus will run at perceived enemies of their chicks, mouth open and wings flapping), sheltering of chicks, etc. If the wings are useless, why are the muscles functional, allowing these birds to move their wings?New Zealand has more species of flightless birds than any other country. One reason is that until the arrival of humans roughly a thousand years ago, there were no large land predators in New Zealand; the main predators of flightless birds were larger birds.The flightless birds of New Zealand are a principal feature of the 'edge ecology' of the country.In an island environment isolated fromthe rest of the world for more than 80 million years, and free of mammal predators, a number of birds developed flightlessness andeccentric habits. Each of them filled different ecological functions; moa and kakapo as forest browsers, takahe as grass eaters, and kiwi and wrens as ground insect eaters - roles taken by mammals in other ecosystems. Many of the birds are unafraid of humans, a common characteristic resulting from the absence of predators, which became deadly when human hunters arrived. The takahe, for example, is the largest living member of the rail family which is found throughout the Southern Oceanic islands.They were hunted until they were rarely found in the 19th century. None were seen after 1900 and it was declaredextinct, but amazingly, 200 pairs were found in a remote region of Fiordland in 1948. The North Island takahe is extinct, but about 220 of the South Island species continue their dramatic brink of extinction existence.Some flightless varieties of island birds are closely related to flying varieties, implying flight is a significant biological cost.The smallest flightless bird is the Inaccessible Island Rail (length 12.5 cm, weight 34.7 g). The largest (both heaviest and tallest) flightless bird, which is also the largest living bird, is the Ostrich (2.7 m, 156 kg), although some extinct species grew to larger sizes.Flightless birds are the easiest to take care of in captivity because they do not have to be caged. Ostriches were once farmed for their decorative feathers. Today they are raised for meat and for their skins, which are used to make leather.There were also other families of flightless birds, such as the now extinct Phorusrhacidae, that evolved to be very powerful terrestrial predators.【托福高频词】evolvedcitationfromderivedroughlypredatorseccentricdramaticextinctterrestrial【长难句分析】It is believed by some citation needed that most flightless birds evolved in the absence of predators on islands, and lost the power of flight because they had few enemies — although this is likely not the case for the ratites (the ostrich, emu and cassowary), as all have claws on their feet to use as a weapon against predators.Some possible functions, depending on the species of flightless bird, are: balance while running, cooling in hot weather, warmth in cold weather, protection of the ribcage during falls, mating rituals, scaring predators (emus will run at perceived enemies of their chicks, mouth open and wings flapping), sheltering of chicks, etc.Many of the birds are unafraid of humans, a common characteristic resulting from the absence of predators, which became deadly when human hunters arrived.相关推荐:托福阅读机经背景：印加古国的书写系统托福阅读机经：英国农业的发展托福阅读机经：婴幼儿的记忆能力相关字搜索：托福阅读机经背景复习。
