剑桥雅思阅读7原文难度解析(test3)
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剑桥雅思阅读7原文(test3)
READING PASSAGE 1
You should spend about 20 minutes on Questions 1-13, which are based on Reading Passage 1 below.
Ant Intelligence
When we think of intelligent members of the animal kingdom, the creatures that spring immediately to mind are apes and monkeys. But in fact the social lives of some members of the insect kingdom are sufficiently complex to suggest more than a hint of intelligence. Among these, the world of the ant has come in for considerable scrutiny lately, and the idea that ants demonstrate sparks of cognition has certainly not been rejected by those involved in these investigations.
Ants store food, repel attackers and use chemical signals to contact one another in case of attack. Such chemical communication can be compared to the human use of visual and auditory channels (as in religious chants, advertising images and jingles, political slogans and martial music) to arouse and propagate moods and attitudes. The biologist Lewis Thomas wrote, ‘Ants are so much like human beings as to be an embarrassment. They farm fungi, raise aphids_as livestock, launch armies to war, use chemical sprays to alarm and confuse enemies, capture slaves, engage in child labour, exchange information ceaselessly. They do everything but watch television.’
However, in ants there is no cultural transmission — everything must be encoded in the genes — whereas in humans the opposite is true. Only basic instincts are carried in the genes of a newborn baby, other skills being learned from others in the community as the child grows up. It may seem that this cultural continuity gives us a huge advantage over ants. They have never mastered fire nor progressed. Their fungus farming and aphid herding crafts are sophisticated when compared to the agricultural skills of humans five thousand years ago but have been totally overtaken by modern human agribusiness.
Or have they? The farming methods of ants are at least sustainable. They do not ruin environments or use enormous amounts of energy. Moreover, recent evidence suggests that the crop farming of ants may be more sophisticated and adaptable than was thought.
Ants were farmers fifty million years before humans were. Ants can’t digest the cellulose in leaves — but some fungi can. The ants therefore cultivate these fungi in their nests, bringing them leaves to feed on, and then use them as a source of food. Farmer ants secrete antibiotics to control other fungi that might act as ‘weeds’, and spread waste to fertilise the crop.
It was once thought that the fungus that ants cultivate was a single type that they had propagated, essentially unchanged from the distant past. Not so. Ulrich Mueller of Maryland and his colleagues genetically screened 862 different types of fungi taken from ants’ nests. These turned out to be highly diverse: it seems that ants are continually domesticating new species. Even more impressively, DNA analysis of the fungi suggests that the ants improve or modify the fungi by regularly swapping and sharing strains with neighbouring ant colonies.
Whereas prehistoric man had no exposure to urban lifestyles — the forcing house of intelligence — the evidence suggests that ants have lived in urban settings for close on a hundred million years, developing and maintaining underground cities of specialised chambers and tunnels.
When we survey Mexico City, Tokyo, Los Angeles, we are amazed at what has been accomplished by humans. Yet Hoelldobler and Wilson’s magnificent work for ant lovers, The Ants, describes a supercolony of the ant Formica yessensis on the Ishikari Coast of Hokkaido. This ‘megalopolis’ was reported to be composed of 360 million workers and a million queens living in 4,500 interconnected nests across a territory of 2.7 square kilometres.
Such enduring and intricately meshed levels of technical achievement outstrip by far anything achieved by our distant ancestors. We hail as masterpieces the cave paintings in southern France and elsewhere, dating back some 20,000 years. Ant societies existed in something like their present form more than seventy million years ago. Beside this, prehistoric man looks technologically primitive. Is this then some kind of intelligence, albeit of a different kind?
Research conducted at Oxford, Sussex and Zurich Universities has shown that when desert ants return from a foraging trip, they navigate by integrating bearings and distances, which they continuously update in their heads. They combine the evidence of visual landmarks with a mental library of local directions, all within a framework which is consulted and updated. So ants can learn too.
And in a twelve-year programme of work, Ryabko and Reznikova have found evidence that ants can transmit very complex messages. Scouts who had located food in a maze returned to mobilise their foraging teams. They engaged in contact sessions, at the end of which the scout was removed in order to observe what her team might do. Often the foragers proceeded to the exact spot in the maze where the food had been. Elaborate precautions were taken to prevent the foraging team using odour clues. Discussion now centres on whether the route through the maze is communicated as a ‘left-right’ sequence of turns or as a ‘compass bearing and distance’ message.
During the course of this exhaustive study, Reznikova has grown so attached to her laboratory ants that she feels she knows them as individuals — even without the paint spots used to mark them. It’s no surprise that Edward Wilson, in his essay, ‘In the company of ants’, advises readers who ask what to do with the ants in their kitchen to: ‘Watch where you step. Be careful of little lives.’
Questions 1-6
Do the following statements agree with the information given in Reading Passage 1?
In boxes 1-6 on your answer sheet, write
TRUE if the statement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if there is no information on this
1 Ants use the same channels of communication as humans do.
2 City life is one factor that encourages the development of intelligence.
3 Ants can build large cities more quickly than humans do.
4 Some ants can find their way by making calculations based on distance and position.
5 In one experiment, foraging teams were able to use their sense of smell to find food.
6 The essay, ‘In the company of ants’, explores ant communication.
Questions 7-13
Complete the summary using the list of words, A-O, below.
Write the correct letter, A-O, in boxes 7-13 on your answer sheet.
Ants as farmers
Ants have sophisticated methods of farming, including herding livestock and growing crops, which are in many ways similar to those used in human agriculture. The ants cultivate a large number of different species of edible fungi which convert 7..............into a form which they can digest. They use their own natural 8..............as weed-killers and also use unwanted materials as 9.............. . Genetic analysis shows they constantly upgrade these fungi by developing new species and by 10..............species with neighbouring ant colonies. In fact, the farming methods of ants could be said to be more advanced than human agribusiness, since they use 11..............methods, they do not affect the 12..............and do not waste 13.............. .
A aphids B agricultural C cellulose D exchanging
E energy F fertilizers G food H fungi
I growing J interbreeding K natural L other speces
M secretions N sustainable O environment
READING PASSAGE 2
You should spend about 20 minutes on Questions 14-26, which are based on Reading Passage 2 on the following pages.
Questions 14-19
Reading Passage 2 has seven sections, A-G.
Choose the correct headings for sections A-F from the list of headings below.
Write the correct number, i-x, in boxes 14-19 on your answer sheet.
List of Headings
i The results of the research into blood-variants
ii Dental evidence
iii Greenberg’s analysis of the dental and linguistic evidence
iv Developments in the methods used to study early population movements
v Indian migration from Canada to the U.S.A.
vi Further genetic evidence relating to the three-wave theory
vii Long-standing questions about prehistoric migration to America
viii Conflicting views of the three-wave theory, based on non-genetic evidence
ix Questions about the causes of prehistoric migration to America
x How analysis of blood-variants measures the closeness of the relationship between different populations
14 Section A
15 Section B
16 Section C
17 Section D
18 Section E
19 Section F
Example Answer
Section G viii
Population movements and genetics
A Study of the origins and distribution of human populations used to be based on archaeological and fossil evidence. A number of techniques developed since the 1950s, however, have placed the study of these subjects on a sounder and more objective footing. The best information on early population movements is now being obtained from the ‘archaeology of the living body’, the clues to be found in genetic material.
B Recent work on the problem of when people first entered the Americas is an example of the value of these new techniques. North-east Asia and Siberia have long been accepted as the launching ground for the first human colonisers of the New World1. But was there one major wave of migration across the Bering Strait into the Americas, or several? And when did this event, or events, take place? In recent years, new clues have come from research into genetics, including the distribution of genetic markers in modern Native Americans2.
C An important project, led by the biological anthropologist Robert Williams, focused on the variants (called Gm allotypes) of one particular protein — immunoglobin G — found in the fluid portion of human blood. All proteins ‘drift’, or produce variants, over the generations, and members of an interbreeding human population will share a set of such variants. Thus, by comparing the Gm allotypes of two different populations (e.g. two Indian tribes), one can establish their genetic ‘distance’, which itself can be calibrated to give an indication of the length of time since these populations last interbred.
D Williams and his colleagues sampled the blood of over 5,000 American Indians in western North America during a twenty-year period. They found that their Gm allotypes could be divided into two groups, one of which also corresponded to the genetic typing of Central and South American Indians. Other tests showed that the Inuit (or Eskimo) and Aleut3 formed a third group. From this evidence it was deduced that there had been three major waves of migration across the Bering Strait. The first, Paleo-lndian, wave more than 15,000 years ago was ancestral to all Central and South American Indians. The second wave, about 14,000-12,000 years ago, brought Na-Dene hunters, ancestors of the Navajo and Apache (who only migrated south from Canada about 600 or 700 years ago). The third wave, perhaps 10,000 or 9,000 years ago, saw the migration from North-east Asia of groups ancestral to the modern Eskimo and Aleut.
E How far does other research support these conclusion? Geneticist Douglas Wallace has studied mitochondrial DNA4 in blood samples from three widely separated Native American groups: Pima-Papago Indians in Arizona, Maya Indians on the Yucatan peninsula, Mexico, and Ticuna Indians in the Upper Amazon region of Brazil. As would have been predicted by Robert Williams’s work, all three groups appear to be descended from the same ancestral (Paleo-lndian) population.
F There are two other kinds of research that have thrown some light on the origins of the Native American population; they involve the study of teeth and of languages. The biological anthropologist Christy Turner is an expert in the analysis of changing physical characteristics in human teeth. He argues that tooth crowns and roots5 have a high genetic component, minimally affected by environmental and other factors. Studies carried out by Turner of many thousands of New and Old World specimens, both ancient and modern, suggest that the majority of prehistoric Americans are linked to Northern Asian populations by crown and root traits such as incisor6 shoveling (a scooping out on one or both surfaces of the tooth), single-rooted upper first premolars6 and triple-rooted lower first molars6.
According to Turner, this ties in with the idea of a single Paleo-lndian migration out of North Asia, which he sets at before 14,000 years ago by calibrating rates of dental micro-evolution. Tooth analyses also suggest that there were two later migrations of Na-Denes and Eskimo-Aleut.
G The linguist Joseph Greenberg has, since the 1950s, argued that all Native American languages belong to a single ‘Amerind’ family, except for Na-Dene and Eskimo-Aleut — a view that gives credence to the idea of three main migrations. Greenberg is in a minority among fellow linguists, most of whom favour the notion of a great many waves of migration to account for the more than 1,000 languages spoken at one time by American Indians. But there is no doubt that the new genetic and dental evidence provides strong backing for Greenberg’s view. Dates given for the migrations should nevertheless be treated with caution, except where supported by hard archaeological evidence.
1 New World: the American continent, as opposed to the so-called Old World of Europe, Asia and Africa
2 modern Native American: an American descended from the groups that were native to America
3 Inuit and Aleut: two of the ethnic groups native to the northern regions of North America (i.e. northern Canada and Greenland)
4 DNA: the substance in which genetic information is stored
5 crown/root: parts of the tooth
6 incisor/premolar/molar: kinds of teeth
Questions 20 and 21
The discussion of Williams’s research indicates the periods at which early people are thought to have migrated along certain routes. There are six routes, A-F, marked on map below.
Complete the table below.
Write the correct letter, A-F, in boxes 20 and 21 on your answer sheet.
Route Period (number of years ago)
20.................. 15,000 or more
21.................. 600 to 700
Early Population Movement to the Americas
Questions 22-25
Reading Passage 2 refers to the three-wave theory of early migration to the Americas. It also suggests in which of these three waves the ancestors of various groups of modern native Americans first reached the continent.
Classify the groups named in the table below as originating from
A the first wave
B the second wave
C the third wave
Write the correct letter, A, B or C, in boxes 22-25 on your answer sheet.
Name of group Wave number
Inuit 22..................
Apache 23..................
Pima-Papago 24..................
Ticuna 25..................
Question 26
Choose the correct letter, A, B, C or D.
Write the correct letter in box 26 on your answer sheet.
Christy Turner’s research involved the examination of
A teeth from both prehistoric and modern Americans and Asians.
B thousands of people who live in either the New or the Old World.
C dental specimens from the majority of prehistoric Americans.
D the eating habits of American and Asian populations.
READING PASSAGE 3
You should spend about 20 minutes on Questions 27-40, which are based on Reading Passage 3 below.
Forests are one of the main elements of our natural heritage. The decline of Europe’s forests over the last decade and a half has led to an increasing awareness and understanding of the serious imbalances which threaten them. European countries are becoming increasingly concerned by major threats to European forests, threats which know no frontiers other than those of geography or climate: air pollution, soil deterioration, the increasing number of forest fires and sometimes even the mismanagement of our woodland and forest heritage. There has been a growing awareness of the need for countries to get together to co-ordinate their policies. In December 1990, Strasbourg hosted the first Ministerial Conference on the protection of Europe’s forests. The conference brought together 31 countries from both Western and Eastern Europe. The topics discussed included the coordinated study of the destruction of forests, as well as how to combat forest fires and the extension of European research programs on the forest ecosystem. The preparatory work for the conference had been undertaken at two meetings of experts. Their initial task was to decide which of the many forest problems of concern to Europe involved the largest number of countries and might be the subject of joint action. Those confined to particular geographical areas, such as countries bordering the Mediterranean or the Nordic countries therefore had to be discarded. However, this does not mean that in future they will be ignored.
As a whole, European countries see forests as performing a triple function: biological, economic and recreational. The first is to act as a ‘green lung’ for our planet; by means of photosynthesis, forests produce oxygen through the transformation of solar energy, thus fulfilling what for humans is the essential role of an immense, non-polluting power plant. At the same time, forests provide raw materials for human activities through their constantly renewed production of wood. Finally, they offer those condemned to spend five days a week in an urban environment an unrivalled area of freedom to unwind and take part in a range of leisure activities, such as hunting, riding and hiking. The economic importance of forests has been understood since the dawn of man — wood was the first fuel. The other aspects have been recognised only for a few centuries but they are becoming more and more important. Hence, there is a real concern throughout Europe about the damage to the forest environment which threatens these three basic roles.
The myth of the ‘natural’ forest has survived, yet there are effectively no remaining ‘primary’ forests in Europe. All European forests are artificial, having been adapted and exploited by man for thousands of years. This means that a forest policy is vital, that it must transcend national frontiers and generations of people, and that it must allow for the inevitable changes that take place in the forests, in needs, and hence in policy. The Strasbourg conference was one of the first events on such a scale to reach this conclusion. A general declaration was made that ‘a central place in any ecologically coherent forest policy must be given to continuity over time and to the possible effects of unforeseen events, to ensure that the full potential of these forests is maintained’.
That general declaration was accompanied by six detailed resolutions to assist national policy-making. The first proposes the extension and systematisation of surveillance sites to monitor forest decline. Forest decline is still poorly understood but leads to the loss of a high proportion of a tree’s needles or leaves. The entire continent and the majority of species are now affected: between 30% and 50% of the tree population. The condition appears to result from the cumulative effect of a number of factors, with atmospheric pollutants the principal culprits. Compounds of nitrogen and sulphur dioxide should be particularly closely watched. However, their effects are probably accentuated by climatic factors, such as drought and hard winters, or soil imbalances such as soil acidification, which damages the roots. The second resolution concentrates on the need to preserve the genetic diversity of European forests. The aim is to reverse the decline in the number of tree species or at least to preserve the ‘genetic material’ of all of them. Although forest fires do not affect all of Europe to the same extent, the amount of damage caused the experts to propose as the third resolution that the Strasbourg conference consider the establishment of a European databank on the subject. All information used in the development of national preventative policies would become generally available. The subject of the fourth resolution discussed by the ministers was mountain forests. In Europe, it is undoubtedly the mountain ecosystem which has changed most rapidly and is most at risk. A thinly scattered permanent population and development of leisure activities, particularly skiing, have resulted in significant long-term changes to the local ecosystems. Proposed developments include a preferential research program on mountain forests. The fifth resolution relaunched the European research network on the physiology of trees, called Eurosilva. Eurosilva should support joint European research on tree diseases and their physiological and biochemical aspects. Each country concerned could increase the number of scholarships and other financial support for doctoral theses and research projects in this area. Finally, the conference established the framework for a European research network on forest ecosystems. This would also involve harmonising activities in individual countries as well as identifying a number of priority research topics relating to the protection of forests. The Strasbourg conference’s main concern was to provide for the future. This was the initial motivation, one now shared by all 31 participants representing 31 European countries. Their final text commits them to on-going discussion between government representatives with responsibility for forests.
Questions 27-33
Do the following statements agree with the information given in Reading Passage 3?
In boxes 27-33 on your answer sheet, write
TRUE if the statement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if there is no information on this
27 Forest problems of Mediterranean countries are to be discussed at the next meeting or experts.
28 Problems in Nordic countries were excluded because they are outside the European Economic Community.
29 Forests are a renewable source of raw material.
30 The biological functions of forests were recognized only in the twentieth century.
31 Natural forests still exist in parts of Europe.
32 Forest policy should be limited by national boundaries.
33 The Strasbourg conference decided that a forest policy must allow for the possibility of change.
Questions 34-39
Look at the following statements issued by the conference.
Which six of the following statements, A-J, refer to the resolutions that were issued?
Match the statements with the appropriate resolutions (Questions 34-39).
Write the correct letter, A-J, in boxes 34-39 on your answer sheet.
A All kinds of species of trees should be preserved.
B Fragile mountain forests should be given priority in research programs.
C The surviving natural forests of Europe de not need priority treatment.
D Research is to be better co-ordinated throughout Europe.
E Information on forest fires should be collected and shared.
F Loss of leaves from trees should be more extensively and carefully monitored.
G Resources should be allocated to research into tree diseases.
H Skiing should be encouraged in thinly populated areas.
I Soil imbalances such as acidification should be treated with compounds of nitrogen and sulphur.
J Information is to be systematically gathered on any decline in the condition of forests.
34 Resolution 1
35 Resolution 2
36 Resolution 3
37 Resolution 4
38 Resolution 5
39 Resolution 6
Question 40
Choose the correct letter, A, B, C or D.
Write the correct letter in box 40 on your answer sheet.
40 What is the best title for Reading Passage 3?
A The biological, economic and recreational role of forests
B Plans to protect the forests of Europe
C The priority of European research into ecosystems
D Proposals for a world-wide policy on forest management
剑桥雅思阅读7原文参考译文(test3)
TEST 3 PASSAGE 1 参考译文：
蚂蚁智能
每当我们想到动物界的智能成员时，头脑中立刻出现的会是猿和猴子。事实上，在昆虫界，某些成员社会生活的复杂程度显示出了相当程度的智能。其中蚂蚁世界就在最近成了主要的观察对象蚂蚁显示出一定认知力的观点也得到了研究人员的肯定。
蚂蚁储存食物，反击外敌，在攻击时用化学信号互相联系。此类化学信号交流可与人类使用视觉和听觉途径(如圣歌、广告形象、铃声、政治标语以及军乐)来激发情绪和传递理念的行为相媲美。生物学家 Lewis Thomas写道：“蚂蚁和人类是如此的相似，都让我们觉得自愧不如。它们培育真菌，把蚜虫作为家畜来饲养，调配军队作战，用化学气雾发出替告和迷惑敌人，俘虏奴隶，忙于育婴，不停地交流信息。除了不看电视它们什么都做。”
然而，蚂蚁的世界里没有文化的传播——所有的技能都必须存储在基因里——而人类的情况却恰恰相反。人类新生儿的基因里只有基本的本能，其他技能则是在成长过程中从社会其他成员身上学习所得。看起来这种文化传承使我们与蚂蚁相比具有巨大的优势。它们从未掌握用火技术，也不知发展为何物，它们培育真菌、饲养蚜虫的技术和五千年前的人类农耕技术相比还算成熟，但却被人类现代的农业综合企业远远超越。
那么蚂蚁真的被人类超越了么?蚂蚁的农耕方式至少是可持续性的。它们不会破坏环境，也不需要使用大量能源。而且，最近的证据表明，蚂蚁的农耕方式可能比过去我们所认为的还要成熟和灵活。
蚂蚁早于人类5000万年就已成为农夫。它们不能消化叶子中的纤维素，但是某些真菌可以。因此蚂蚁在巢穴里培育这些真菌，让它们以叶子为食，而真菌则成为蚂蚁的食物来源。蚂蚁农夫们分泌抗生素去控制其他可能成为“杂草”的真菌，还会播撒废料来给作物施肥。
曾经有观点认为蚂蚁培育的真菌只是它们繁殖的单一品种，长久以来都没有本质的改变。其实不然。马里兰州的Ulrich Mueller和他的同事们就从蚂蚁巢穴中从基因方面筛选出了862种不同种类的真菌。这些真菌品种多样——看来蚂蚁在不断培育新的真菌品种。让人更加印象深刻的是，对真菌的DNA分析表明， 蚂蚁通过频繁地和周边蚂蚁群体的交换和共享来改进或更新菌种。
史前人类没有机会接触城市化的生活方式——这一孕育智能的温床。而证据表明，蚂蚁已经在城市环境中生存了将近一亿年了，建造并维持着由特殊的洞穴和隧道构成的地下城市。
当我们考察墨西哥城、东京和洛杉矶时，都会惊叹人类的伟大成就。然而，Hoelldobler和Wilson在为蚂蚁爱好者创作的巨著《蚂蚁》中，描述了日本北海道石狩湾的石狩红蚁所建造的超级蚁群。据称，在这个包含了4500个纵横交错的巣穴、幅员达2. 7平方公里的“巨大城市”中，生活着3. 6亿只工蚁和100万只蚁后。
如此坚固，复杂的网状技术成就远远超越了我们的远古祖先所取得的任何成就。人们在法国南部或者其他地方欣赏那些两万年前的岩画杰作的时候对祖先的成就肃然起敬。而蚂蚁的社会形态早在7000多万年前就已经和现在相差无几。此外，史前人类的技术看上去很原始。那么，和当时的蚂蚁社会相比，这还能算是另外一种形式的智能吗?
在牛津大学、苏赛克斯大学以及苏黎世大学所作的研究表明，沙漠蚁在觅食归巢途中，会结合它们脑中不断更新的方向和距离资料来做导向。它们会将可见的地标与记忆库中的区域方向结合来分门别类储存，并不断地使用和更新。因此蚂蚁也具备学习能力。
在12年研究过程中，Ryabko和Reznikova找到了证据，证明蚂蚁能够传递非常复杂的信息。侦察蚁在迷宫中找到食物后返回去通知觅食队伍。研究人员干涉了蚂蚁交流的过程，在最后把侦察蚁弄走，看蚂蚁团队会有什么反应。通常觅食队伍会还是能够继续行进到迷宫中食物的确切位置。而在此之前，研究人员已经做了精密的预防措施，防止蚁群通过气味来传递信息。现在讨论的焦点是，蚂蚁在迷宫中行进路线的传递是通过一连串的左转、右转信息还是通过指南针式的方向和距离引导来完成的。
在这次全面的研究过程中，Reznikova全身心地投入到她实验室的蚂蚁身上，她感觉己认识每一只蚂蚁——即使它们身上没有记号。无怪乎Edward Wilson在他的论文《与蚂蚁相伴》中，建议那些询问如何处理厨房中蚂蚁的读者：“注意脚下，珍惜小生命。”
TEST 3 PASSAGE 2 参考译文：
人口迁移与遗传学
A过去人们对人类起源与人口分布的研究一直是在考古发现和化石证据的基础上进行的。然而，从20世纪50年代起发明的不少新技术使得此项研究拥有更充分、更客观的立足点。关于人口迁移活动的最早信息是从“活体考古”中获得的，专家们可从遗传物质中发现一些线索。
B 近来对人类何时初次踏上美洲大陆问题的研究便是体现这些新技术价股的最好范例。很久以来，东北亚和西伯利亚就一直被视为人类首次向“北美新世界”迁移的发源地。但是，跨越白令海峡进人美洲大陆的移民浪潮是一次还是几次?这次移民事件，或者这几次事件又适何时发生的呢?近些年来，通过对遗传学的研究，专家们找到遗传标记在现代美国本土居民中分布情况的新线索。
C 由生物人类学家罗伯特?威廉姆斯领导的一项程把研究点聚焦在了免疫球蛋白G变体(又叫做免疫球蛋白同种异型Gm)上。在人类血液流体中可以找到这种变体。所有的蛋质都处于漂流状态，或者在生产新变体，那么数代之后，通过通婚形成的家族成员们将会拥有一套共同的变体。所以，通过对比两类不同人群的Gm同种异型(比如两个印第安人部落)人们可以建立各自的“遗传距离”，距离本身可以调整，从而可以给出一些信息，提示此族群自从最后一次通婚混血以来经过了多长吋间。
D威廉姆斯和他的同事们花费20年时间在北美西部地区采集了5, 000名美洲印第安人的血液标本。通过研究发现，这些印第安人的Gm同种异型可以划分为两组，其中一组也和中部、南部的印第安人基因类型相匹配。其他测试显示因纽特人(又叫爱斯基摩人)和阿留申人形成另一个族群。据此证据可推断出，跨越白令海峡的大规模移民浪潮共有三次。第一次移民浪潮发生在15,000年前，其中的古印第安人是今天美国中部和南部印第安人的祖先。约14, 000到12, 000年前的第二次移民浪潮带来了纳迪尼狩猎者，他们是纳瓦乔人和阿帕切人(他们在约600或700年前从加拿大南部移民美国)的祖先。第三次浪潮发生在约10, 000或 9,000年前，从东北亚移民至北美大陆的这批人是现代爱斯基摩人和阿留申人的祖先。
E那么，其他研究对此项结论的支持力度又有多大呢?遗传学专家道格拉斯?华莱士通过研究三大彼此远离的本土美洲人(亚利桑那州的皮马-帕帕戈人、墨四哥尤卡坦半岛的玛雅印第安人、巴西亚马逊河上游流域的迪古拿印第安人)血液样本中的线粒体DNA发现：就像罗伯特?威廉姆斯的著作预测的那样，三个族群其实源于同一个祖先。
F此外，还有两种研究进一步阐明了本土美洲人的起源问题它们涉及牙齿研究和语言研究。生物人类学家克里斯蒂?特纳是一位从事人类牙齿生理特征变化研究的专家。他认为齿冠和齿根包含极高的遗传因素，受环境和其他因素影响很小。根据对数千年来自新旧世界的样本进行分析，特纳发观，大多数史前美洲人在齿冠和齿根特点上和亚洲北部人口有所联系，如铲形门齿(牙齿单侧或双侧边缘嵴隆起而中部呈凹窝状)，单重根上齿第一前磨牙和三重根下前第一磨牙。
据特纳称，这一特点和古印第安从北亚向外移民有所关联，特纳通过研究牙齿微进化速度得出这次移民发生在14，000年前。通过对牙齿的研究也发现了后面还有科纳迪尼和爱斯基摩-阿留申这两次移民浪潮。
自从20世纪50年代，语言学家约瑟夫?格林怕格就认为，所有的本土美国语言同属于唯一的一个印第安语系(除纳迪尼和爱斯堪摩-阿留申以外)，此种观点对三大主要移民浪潮的说法提供了凭证。格林伯格是同时代语言学家中的少数派，而大多数语言学家都赞成这样一种观点：一波又一波的移民浪潮解释那一时期北美印第安人讲1000多种语言的唯一依据。但是毫无疑问，新的遗传学和牙齿证据为格林伯格的观点提供了强有力的支持。当然，关于移民的具体时间问题也要谨慎对待，除非这些信息有确凿的考古证据的支撑。
TEST 3 PASSAGE 3 参考译文：
欧洲森林保护计划
森林是自然遗产的主要元素之一。过去15年欧洲森林的退化程度已经逐渐让人们意识并了解到这种严重失调对他们的威胁。欧洲国家越来越重视欧洲森林受到的主要威胁，除了地理和气候性的威胁以外，其他的都是不分国界的，诸如空气污染、土壤退化、与日俱增的森林火灾，有时候甚至是我们对林地和森林的管理不善。人们也越来越清楚地认识到各国需要联合起来协调政策。1990年12月，在法国斯特拉斯堡举行了第一次以保护欧洲森林为主题的部长级会议，来自东西欧的31国家代表汇集一堂。会议的议题包括： 如何协调研究对森林的破坏，如何防范森林火灾，以及欧洲森林生态系统研究项目的扩大。会议举行前召开了两次专家会议来做会前准备工作。他们最初的任务是决定在欧洲森林所面临的诸多问题中，哪个问题所涉及的国家最多，可作为各国联合行动的主题。因此那些受特殊地理条件限制的地区，如地中海以及北欧国家就被排除在外了。但是以后他们还是有可能参与进来的。
总体而言，欧洲国家认为森林有三重功能——生物、经济和娱乐功能。第一重是扮演地球的“绿色之肺”;通过光合作用，森林在太阳能量转换过程中释放。对人类而言，它是不可替代的巨大而无污染的能量来源。同时，通过不断再生的木材，森林还为人类活动提供了原材料。最后，森林还为那些在城市里每周五天深陷于工作的上班族们提供了无与伦比的自由氛围去释放心情，参与游猎、骑马以及远足等休闲活动。森林的经济功能从人类起源开始就被发现了——木材就是最初的燃料。其他功能的发现仅有几个世纪的历史，但它们变得越来越重要。因此，整个欧洲十分关注威胁到森林使其不能扮演这三重基本功能的破坏性行为。
有关天然森林的古老神话还在欧洲大陆流传着，而事实上，真正的原始森林已经不复存在了。所有的欧洲森林都是人工种植的，被人类改造和开发了数千年。这就意味着，一项超越国界、跨越年代的森林政策至关重要，并且必须要考虑到森林环境、人民需求，国家政策发生不可避免的变化。斯特拉斯保会议是同等规模的活动中最先达成该结论的活动之一。其总宣言为：任何具有生态延续性的森林政策的核心内容，都必须着眼于长期的可持续性以及不可预见的状况可能带来的影响，以保证森林的全部潜能都可以得到维系。
除了总宣言，会议还提出了六项有利于国家政策制定的详细决议。第一项决议是对森林退化监测站进行扩建并使其系统化。我们对森林退化的了解还不多，但它会造成树叶和针叶的大量脱落。整个欧洲大陆以及大多数树种都受到影响，受影响树木占树木总量的30%到50%这样的情况像是由一系列因素累积导致的，大气污染就是其中的罪魁祸首。还需要特別注意氮化物和二氧化硫。然而，一些气候因素如干旱、寒冬，以及破坏树木根系的土壤酸化等土地失衡状况，可能会加剧这些不利因素的影响。第二项决议的重点是保持欧洲森林基因多样性的需求。目标是改变树种减少的状况或者至少保留所有树种的基因资料。虽然森林大火对欧洲各国的影响程度不同，但是其破坏力却让专家们提出第三个决议：斯特拉斯堡会议应该考虑就此主题建立一个欧洲数据库。所有国家保护政策发展过程中所用的信息将被广泛分享。部长们所讨论的第四项决议是关于山林的。在欧洲变化最快、处境最危险的无疑是山地生态系统，常住人口的零星分布以及休闲活动特别是滑雪，给当地生态系统造成了严重而长期的改变。建议的改进措施包括优先建立一项关于山林的研究项目。第五项决议重新发布了有关树木生理学的名为“森林持续发展”的欧洲研究网“森林持续发展”将支持欧洲各国联合研究树木的病害以及生理和生化方面的问题。每个参与国都可以增加奖学金以及其他经济支持来鼓励此领域博士论文的撰写以及研究项目的开展。会议最终建立了欧洲森林生态系统的科研网络，用以协调各国行动以及确认一些和森林保护相关的重点研究议题，斯特拉斯堡会议的重点是着眼于未来。这一最初的动机现在已成为31名参加者代表的31个欧洲国家的共同动力。他们最后的承诺是肩负起对森林的责任，保证政府代表间相关的讨论交流。
剑桥雅思阅读7原文解析(test3)
Test 3 Passage 1
Question 1
答案：FALSE
关键词：channels, communication, humans
定位原文: 第2段第2、3句: “Such chemical communication can be… Ants are so much like …”
解题思路: 此题可以通过定位词迅速定位第2段的这两句话。两句话中都只是说明蚂蚁的生物行为与人类非常相似，而题目中则说是“相同”，与原文相悖，因此答案很明显应该是 FALSE 。
Question 2
答案：TRUE
关键词：city life, intelligence
定位原文: 第7段第1句: “Whereas prehistoric man had …” 此题的定位比较有难度，定位词并未以原形出现。但若根据顺序原则由第3题的定位段落(第8段)向前查找会比较容易。
解题思路: 文章与题目出现同义转换：urban life — city life; forcing house — encourages
该题的解题关键在于是否能正确理解文中短语forcing house的含义，它的含义为“温床”， 与题中解题关键字：encourages完全吻合。因此此题答案为TRUE。
Question 3
答案： NOT GIVEN
关键词：build large cities
定位原文: 第8段第1句: “...we’re amazed at what has been accomplished by humans.”
第9段第1句: “Such enduring and intricately meshed levels…”
解题思路: 文章第8段提到了人类建造城市的例子，第9段指出蚂蚁的技术远远超过我们的祖先，但是文章并未提到蚂蚁和人类的建造速度，也未对此作任何的比较。此题属于典型的文章未提及型题目，因此应该选择NOT GIVEN。
Question 4
答案：TRUE
关键词：distance and position
定位原文: 第10段第1句: “...they navigate by integrating bearings and distances...”它们通过整合方向和距离来导航。
解题思路: 此题通过定位词可以迅速定位到第10段该句，且该句含义与题目一致。 文章与题目出现同义转换：find their way — navigate; making calculations — integrating; bearings — position. 因此此题答案为TRUE。
Question 5
答案：FALSE
关键词：foraging teams
定位原文: 第11段倒数第2句: “Elaborate precautions were…”
解题思路: 此题利用定位词很容易定位，且文中定位处出现prevent...using odour clues，其含义为防止使用气味线索，而题干中的解题要点为蚂蚁使用嗅觉寻找食物。很明显，此题题干与原文内容相悖，因此答案为FALSE。
Question 6
答案：NOT GIVEN
关键词： “In the company of ants”
定位原文: 末段最后1句：“...in his essay, ‘In the company of ants’, advises …”
解题思路: 此题定位非常容易。在定位句中，作者仅仅强调了需要将蚂蚁视为有智能的生命来对待，对于题干中的解题点“蚂蚁的信息交流”是否进行研究并未提及。此题属于典型的“题干信息文章部分提及”，因此此题答案为NOT GIVEN。
Question 7
答案： C
关键词：cultivate, they can digest
定位原文: 第5段第2、3句：“Ants can’t digest… The ants therefore…”
解题思路:此题通过在定位段落第5段中扫描定位词，可以将其定位在第2、3句，其含义为“蚂蚁不能消化叶子中的纤维素，但是一些真菌可以。因此蚂蚁在自己的巢中培养这些真菌”。题干中此题应填一个名词，且根据其后信息判断出该名词在经过转变后能被蚂蚁消化，于是可以直接选出答案C。
Question 8
答案： M
关键词：weed-killers
定位原文: 第5段最后1句: “Farmer ants secrete antibiotics…”
解题思路: 按照顺序原则在第7题后扫描定位词可以迅速定位。通过阅读此空之后的题干信息可推出所填单词应为名词，且其行为为kill weeds;通过扫描定位句，其中满足条件的词为antibiotics，但在词库中并未出现，此时只能选出其上下义词，即为选项M。
Question 9
答案：F
关键词： unwanted materials
定位原文: 第5段最后1句: “...and spread waste to fertilise the crop.”
解题思路: 此题在文中定位紧接着上一题。通过题干中空格之前的信息可以判断出所填词为复数名词，且其等价于unwanted materials。在文中定位处找到其对应词waste,且其作用为fertilise the crop;在题目所给词库中的复数名词里进行快速扫描，答案只能为F。
Question 10
答案：D
关键词：new species, neighbouring ant colonies
定位原文: 第6段最后1句: “…the ants improve or modify …”
解题思路: 通过分析空格判断出所填词应为v+ing形式(and前后结构相同)，在文中定位句中对应词为swapping and sharing (交换和分享);在题目所给词库中满足v+ing形式的词里进行快速扫描，答案只能为D。
Question 11
答案：N
关键词：agribusiness, methods
定位原文: 第4段第2、3句：“The farming methods ... They do not ruin…”
解题思路: 此题出现了乱序，但是通过扫描定位词还是可以迅速在文中找到对应词。首先是出现在第3段最后1句话中的agribusiness，接下来才是第4段第2句中的farming methods。通过分析题干中空格前后的信息，判定所填单同应为形容词，且其修饰对象为methods;在文中定位处的对应词为 sustainable，对应答案N。
Question 12
答案： O
关键词：affect
定位原文: 第4段第2、3句: “The farming methods... They do not ruin…”
解题思路:由于空格之前为动词，所以应回原文找寻该动词或其同义词;在文中定位处对应词为ruin, 所以答案为其后单词environment，即O选项
Question 13
答案： E
关键词：waste
定位原文: 第4段第2、3句: “The farming methods ... They do not ruin…”
解题思路: 文中定位处对应词为use enormous amounts of，所以答案为其后单词energy，即E选项。
Test 3 Passage 2
Question 14
答案：iv
关键词：developments
定位原文: A段第2句: “A number of techniques…”
解题思路: A段中间部分出现转折句，主要含义为一系列的新技术使得该研究变得更加良性和客观。在段义选项中只有iv选项中的关键词developments能与之匹配，因此答案为iv。
Question 15
答案：vii
关键词：problem
定位原文: B段首句: “Recent work on the problem…”
解题思路: B段首句引出了首次进入美洲大陆人口的问题，在段义选项中只有vii和ix满足条件，但是B段并未提到人类迁移的原因，而只是在段落后半部分提出了一系列的问题，所以ix不对，答案应该为vii。
Question 16
答案：x
关键词：two different populations; establish their genetic “distance”
定位原文: C段末句: “Thus, by comparing…”
解题思路: C段中提出了一种研究方法，即研究variants，并在最后由thus引出了结论，通过比较两类不同人群就能建立他们之间的“遗传距离”。在段义选项中只有最后一个满足要求，其中对应关键词为 blood-variants, closeness, between different populations，因此答案为x。
Question 17
答案：i
关键词：found that
定位原文: D段第2句: “They found that…”
解题思路: 此段大意其实可以按照逻辑发展顺序迅速地确定为i，这是因为上一段介绍了一个研究，此段应该介绍研究结果，而段义选项中只有i为研究结果。或者通过通读全段，得出主题句为：他们发现这些Gm可以分为两大类。这就是研究的结论，从其后文字均为介绍性文字，也可以判定此段段义为选项i。
Question 18
答案：vi
关键词：other research
定位原文: E段首句: “How far does other research support these conclusions?”
解题思路: E段首句即提出了其他研究是否能支持上一段结论的问题，然后列举出了其他实验的例子。在段义选项中，只有vi选项中提到了其他研究(further genetic evidence),故答案是vi。
Question 19
答案：ii
关键词：dental
定位原文: F段第2句：“The biological anthropologist Christy Turner is…”
解题思路: 此段首句极具迷惑性，其含义为另两种关于牙齿和语言的研究也能解释这个问题，所以可能错选 iii，因为其中包含关键词dental and linguistic evidence，但是iii中人物Greenberg仅出现在下一段，故排除此选项。此段真正主题句为第二句，此句介绍了研究牙齿也能解释问题，其后文字全部为介绍牙齿研究的文字，故答案为ii。
Question 20
答案：E
关键词：15, 000 or more
定位原文: D段中部倒数第4句： “...three major waves of migration…”
解题思路: 定位处说明了此处的wave应该across the Bering Strait，所以答案应该在B、C、E中筛选，在图中可以很明显地定位出原文相关词Central American和 South American，故答案为其对应选项E。
Question 21
答案：D
关键词： 600 to 700
定位原文: D段后半部倒数第2句: “... and Apache (who only migrated south from Canada about 600 or 700 years ago).”
解题思路: 定位处的说明为：仅仅在600或700年前从加拿大向南部迁移。
在图中各条箭头中只有D的起点在Canada，且箭头方向向南，故答案为D。
Question 22
答案：C
关键词： Inuit
定位原文: D段第3句: “Other tests showed…”
解题思路:
由此句可以很明显地判断出Inuit属于第三类，因此答案为C。
Question 23
答案：B
关键词： Apache
定位原文: D段倒数第2句: “The second wave…”
解题思路:
由此句可以很明显地判断出Apache属于第二类，因此答案为B。
Question 24
答案：A
关键词：Pima-Papago
定位原文: E段第二句: “...blood samples from three widely separated Native American
…” E段最后一句: “… all three groups appear to be descended…”
解题思路: 通过定位句可判定Pima-Papago属于 “three groups”中的一种，且均来自于 Paleo-lndian; Paleo-lndian在D段倒数第三句出现过：The first，Paleo-lndian，wave...故答案为A
Question 25
答案： A
关键词：Ticuna
定位原文: E段倒数第2句: “… and Ticuna Indians in the Upper Amazon region of Brazil…” D段倒数第三句: “The first, Paleo-lndian, wave … was ancestral to all Central and South American Indians”.
解题思路:定位这两句，可以发现Ticuna Indians也属于first wave
Question 26
答案： A
关键词：Christy Turner
定位原文: 通过题干粗定位于文章F段第2句: “Christy Turner is an expert …” F段最后一句: “Studies carried out by…”
解题思路: 通过F段第2句可知：特纳的研究主要是分析人类牙齿的生理特征，因此可以排除未提及牙齿的选项 B和D。C选项极具迷惑性，其中“the majority of prehistoric Americans”与全文一致，但是这一内容只是实验结果所“suggest”的，而并非特纳真正的实验内容;A选项与原文 “Studies...of many thousands of New and Old World specimens，both ancient and modem”含义完全一致。故正确答案为A。
Test 3 Passage 3
Question 27
答案：NOT GIVEN
关键词： Mediterranean countries
定位原文: 第1段末最后两句: “…such as counties bordering Mediterranean … However, this dose not mean…”
解题思路: 此题通过定位词可以迅速定位到第一段最后两句话，其含义为地中海国家在日后不一定被忽略;而题干则为在下次会议中会讨论，显然为文中未提及内容。故此题答案为NOT GIVEN。
Question 28
答案：FALSE
关键词：Nordic countries
定位原文: 第1段末倒数第3句和倒数第2句：“Their initial task was to… Those confined to particular geographical areas…”
解题思路: 该题考查因果关系，由定位句中的因果关系词therefore推出解题句为定位句的前一句：Nordic countries不被考虑是因为会议要决定哪些森林问题涉及的国家最多并且能够成为联合行动的主题，这与题干中的原因不同，而考查因果关系时要求文章与题目精确，故此题答案为FALSE。
Question 29
答案：TRUE
关键词： raw material
定位原文: 第2段第3句: “forests provide raw materials…”
解题思路: 此题的定位词在文中以原词出现，按照顺序原则可以迅速定位。文中定位处含义为：通过其不断再生的木材，森林给人类活动提供了原材料。文章与题目含义一致。故此题答案为TRUE。
Question 30
答案：FALSE
关键词：biological functions, recognised
定位原文: 第2段倒数第3句、倒数第2句: “The economic importance of forests has been... The other aspects have been…”
解题思路: 此题先通过biological functions定位于第二段首句，其中提到森林的三种功能为 biological，economic和recreational;然后由recognised精确定位到解题句，其中提到除了economic之外的两方面都已经被认可了几个世纪，而题目却认为其仅仅是在20世纪才被认可的。题目明显与文章相悖，故此题答案为FALSE。
Question 31
答案：FALSE
关键词：natural forests
定位原文: 第3段第2句: “All European forests are artificial”
解题思路: 此题通过定位词可定位于第3段首句，通过扫读得出解题句，其含义为：欧洲所有的森林都是人工种植的，很显然题目与文章内容刚好相反，故此题答案为FALSE。
Question 32
答案：FALSE
关键词：forest policy, national boundaries
定位原文: 第3段第3句: “This means that…”
解题思路: 此题通过定位词能够迅速定位。定位句的含义为：森林政策至关重要，它必须超越国家的界限。显然题目与文章内容相反，故此题答案为FALSE。
Question 33
答案：TRUE
关键词： Strasbourg conference, forest policy, change
定位原文: 第3段第3句、第4句：“This means that a forest policy… The Strasbourg conference was…”这就意味着一项森林政策至关重要，它必须考虑到森林环境，人民需求，国家政策发生不可避免的变化。斯特拉斯堡会议也成为此类髙规格创始会议中达成该结论的会议之一。
解题思路: 此题通过定位词能够迅速定位。定位句指出会议达成this conclusion，此处出现指代，按“遇指代，向前看一句”的原则得到定位句首句。定位句中结论与题目含义一致，故此题答案为 TRUE。
Question 34
答案：J
关键词：resolution 1
定位原文: 第4段第2句: “The first proposes the extension…” 第一项决议是对森林退化监测站进行扩建并使其系统化。
解题思路: 在选项中扫描关键词，只有J选项符合该含义：森林的任何退化信息都将被系统地收集。此处有两个干扰选项，F和I。F选项中出现文中原词monitored，但对loss of leaves的监测只是决议I中的一项内容，不全面。 I选项中出现文中原词 soil imbalance, acidification, compounds of nitrogen and sulphur，但这些词在文中分別出现于不同的例子中，而I选项却将其揉在一句话中。 故答案为J。
Question 35
答案： A
关键词：resolution 2
定位原文: 第4段中部第8句: “The second resolution concentrates on…”第二项决议的重点是保持欧洲森林站基因多样性的需求。
解题思路: 在选项中扫描关键词，只有A选项出现关键词preserve, 且其含义与原文相符：所有种类的树木都必须被保存。故答案为A。
Question 36
答案： E
关键词：resolution 3
定位原文: 第4段第10句：“Although forest fires do not...” 虽然森林大火对欧洲各国的影响程度不同，但是其破坏力却让专家们提出第三个决议：斯特拉斯堡会议应该考虑就此主题建立一个欧洲数据库
解题思路: 在选项中扫描关键词，只有E选项出现关键词forest fires，且其含义与原文相符：有关森林大火的信息需被收集并分享。故答案为E。
Question 37
答案： B
关键词：resolution 4
定位原文: ：第4段倒数第9句: “Proposed developments include…” 建议的改进措施包括优先建立一项关于山林的研究项目。
解题思路: 在选项中扫描关键词，只有B选项出现关键词mountain forests和priority (对应 preferential), 且其含义与原文相符：脆弱的山林应该在研究项目中优先考虑, 故答案为B。
Question 38
答案：G
关键词：resolution 5
定位原文: 第4段倒数第8句、倒数第7句：“Eurosilva should support... Each country concerned could…”“森林持续发展”将支持欧洲各国联合研究树木的病害以及生理和生化方面的问题。每个参与国都可以增加奖学金以及其他经济支持来鼓励此领域博士论文的撰写以及研究项目开展。
解题思路: 在选项中扫描关键词，只有G选项出现关键词allocated to research和tree diseases, 且其含义与原文相符：资源必须分配给关于树木病害的研究。
故答案为G。
Question 39
答案： D
关键词：resolution 6
定位原文: 第4段倒数第5句：“Finally, the conference established…”会议最终建立了欧洲森林生态系统的科研网络
解题思路: 在选项目扫描关键词，只有D选项出现关键词co-ordinated(对应research network), 且其含义与原文相符：研究最好在整个欧洲范围内进行，以便更好地相互协作。故答案为D。
Question 40
答案： B
关键词： 无
定位原文: 全文结构
解题思路: 通过分析文中首句可以得出，其中关键词为forests，从而排除不含此关键词的选项C; A选项中的三个关键词biological, economic和recreational均未在末句中提及，故排除;B和D两个选项中关键词分別为：B强调protect，D强调policy on management。文章末句中government以及responsibility for forests强调政府对于森林的责任而并非管理，排除D选项。故正确答案为B。
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