Bird migration（鸟类迁徙）
A
Birds have many unique design features thatenable them to perform such amazing feats of endurance. They are equipped withlightweight, hollow bones, intricately designed feathers providing both liftand thrust for rapid flight, navigation systems superior to any that man hasdeveloped, and an ingenious heat conserving design that, among other things,concentrates all blood circulation beneath layers of warm, waterproof plumage,leaving them fit to face life in the harshest of climates. Their respiratorysystems have to perform efficiently during sustained flights at altitude, sothey have a system of extracting oxygen from their lungs that far exceeds thatof any other animal. During the later stages of the summer breeding season,when food is plentiful their bodies are able to accumulate considerable layersof fat, in order to provide sufficient energy for their long migratory flights.
B
The fundamental reason that birds migrateis to find adequate food during the winter months when it is in short supply.This particularly applies to birds that breed in the temperate and Arcticregions of the Northern Hemisphere, where food is abundant during the shortgrowing season. Many species can tolerate cold temperatures if food isplentiful, but when food is not available they must migrate. However,intriguing questions remain.
C
One puzzling fact is that many birdsjourney much further than would be necessary just to find food and goodweather. Nobody knows, for instance, why British swallows, which couldpresumably survive equally well if they spent the winter in equatorial Africa,instead fly several thousands of miles further to their preferred winter home inSouth Africa Cape Province. Another mystery involves the huge migrationsperformed by arctic terns and mud flat-feeding shorebirds that breed close toPolar Regions. In general, the further north a migrant species breeds, thefarther south it spends the winter. For arctic terns this necessitates anannual round trip of 25,000 miles. Yet, en route to their final destination infar-flung southern latitudes, all these individuals overfly other areas ofseemingly suitable habitat spanning two hemispheres. While we may not fullyunderstand birds' reasons for going to particular places, we can marvel attheir feats.
D
One of the greatest mysteries is how youngbirds know how to find the traditional wintering areas without parentalguidance. Very few adults migrate with juveniles in tow, and youngsters mayeven have little or no inkling of their parents' appearance. A familiar exampleis that of the cuckoo, which lays its eggs in another species nest and neverencounters its young again. It is mind boggling to consider that, once raisedby its host species, the young cuckoo makes its own way to ancestral winteringgrounds in the tropics before returning single-handed to northern Europe thenext season to seek out a mate among its own kind. The obvious implication isthat it inherits from its parents an inbuilt route map and direction-findingcapability, as well as a mental image of what another cuckoo looks like. Yetnobody has the slightest idea as to how this is possible.
E
Mounting evidence has confirmed that birdsuse the positions of the sun and stars to obtain compass directions. They seemalso to be able to detect the earth's magnetic field, probably due to havingminute crystals of magnetite in the region of their brains. However, truenavigation also requires an awareness of position and time, especially whenlost. Experiments have shown that after being taken thousands of miles over anunfamiliar landmass, birds are still capable of returning rapidly to nestsites. Such phenomenal powers arc the product of computing a number ofsophisticated cues, including an inborn map of the night sky and the pull ofthe earth's magnetic field. How the birds use their 'instruments’ remains unknown, but one thing isclear: they see the world with a superior sensory perception to ours. Mostsmall birds migrate at night and take their direction from the position of thesetting sun. However, as well as seeing the sun go down, they also seem to secthe plane of polarized light caused by it, which calibrates their compass.Traveling at night provides other benefits. Daytime predators are avoided andthe danger of dehydration due to flying for long periods in warm, sunlit skiesis reduced. Furthermore, at night the air is generally cool and less turbulentand so conducive to sustained, stable flight.
F
Nevertheless, all journeys involveconsiderable risk, and part of the skill in arriving safely is setting off atthe right time. This means accurate weather forecasting, and utilizingfavorable winds. Birds are adept at both, and, in laboratory tests, some havebeen shown to detect the minute difference in barometric pressure between thefloor and ceiling of a room. Often birds react to weather changes before thereis any visible sign of them. Lapwings, which feed on grassland, flee west fromthe Netherlands to the British Isles, France and Spain at the onset of a coldsnap. When the ground surface freezes the birds could starve. Yet they returnto Holland ahead of a thaw, their arrival linked to a pressure change presagingan improvement in the weather.
G
In one instance a Welsh Manx shearwatercarried to America and released was back in its burrow on Skokholm Island, offthe Pembrokeshire coast, one clay before a letter announcing its release!Conversely, each autumn a small number of North American birds arc blown acrossthe Atlantic by fast-moving westerly tail winds. Not only do they arrive safelyin Europe, but, based on ringing evidence, some make it back to North Americathe following spring, after probably spending the winter with European migrantsin sunny African climes.
Questions 14-20
Reading passage 2 has seven paragraphs, A-G
Choose the correct heading for eachparagraph from the list of headings below. Write
the correct number, i-x, in boxes 14-20 onyour answer sheet.
List of headings
i. The best moment to migrate
ii. The unexplained rejection of closerfeeding ground
iii. The influence of weather on themigration route
iv. Physical characteristics that allowbirds to migrate
v. The main reason why birds migrate
vi. The best wintering grounds for birds
vii. Research findings on how birds migrate
viii. Successful migration despite troubleof wind
ix. Contrast between long-distancemigration and short-distance migration
x. Mysterious migration despite lack ofteaching
14 Paragraph A
15 Paragraph B
16 Paragraph C
17 Paragraph D
18 Paragraph E
19 Paragraph F
20 Paragraph G
Questions 21-22
Choose TWO letters, A-E.
Write the correct letters in boxes 21 and22 on your answer sheet.
Which TWO of the following statements aretrue of bird migration?
A Birds often fly further than they needto.
B Birds traveling in family groups aresafe.
C Birds flying at night need less water.
D Birds have much sharper eye-sight thanhumans.
E Only shorebirds are resistant to strongwinds.
Questions 23-26
Complete the sentences below using NO MORETHAN TWO WORDS from the
passage.
Write your answers in boxes 23-26 on youranswer sheet.
23 It is a great mystery that young birdslike cuckoos can find their wintering grounds without ________.
24 Evidence shows birds can tell directionslike a ________by observing the sun and the stars.
25 One advantage for birds flying at nightis that they can avoid contact with ______.
26 Laboratory tests show that birds candetect weather without ________signs.
中文翻译：Birdmigration（鸟类迁徙）
| A | 鸟类有许多独特的结构特征，使得它们表现出令人惊叹的耐久力。鸟类拥有极轻的体重、中空的骨骼、复杂的羽毛，这些为快速飞行提供了上升力和推动力。同时，鸟类还拥有比人类发明的任何导航系统都要优越的导航体系。此外，它精密的热保护结构会保证其温暖防水羽毛之下的血液循环的畅通，以便它们能够适应最恶劣的气候环境。鸟类必须具备极为髙效的呼吸系统才能适应高空的持久飞行，因此，它们从肺部提取氧气的呼吸系统比任何其他物种的都高效得多。在食物丰富的夏季繁殖季后期，它们的体内会储存大暈脂肪层，为它们长途迁徙飞行提供充足的能量。 |
| B | 鸟类迁徙主要是为了在冬季食物短缺时寻找到足够的食物。尤其是那些生长在北半球温带和北极圈地区的鸟类，因为这些地方只有在短暂的生长季节才会有充足的食物。在食物充足的情况下，很多鸟类都能忍受寒冷的天气，但当食物缺乏时，它们就不得不迁徙。然而，目前还存在一些令人不解的问题。 |
| C | ―个令人不解的现象是，很多鸟类的旅程距离远远长于它们为寻找食物和好天气所必须飞行的距离。例如，没人知道为什么本可以在非洲赤道区过冬的英国燕子非要不远千里飞到南非的开普省过冬。另一个谜团则是关于北极燕鸥以及在北极附近滩涂区哺育生活的水禽的大规模迁徙活动。通常，鸟类生活繁殖的地方越偏北，其冬季迁徙的地方就越偏南。对于北极燕鸥来说，它们每年的旅程长达25,000英里，但是，在飞往遥远的位于南纬度地区的目的地的途中，所有这些鸟类都会飞越许多地跨两个半球，看上去适合栖息的地区。虽然我们可能无法完全理解鸟类前往特定地区的原因，但是，我们也对鸟类游历世界的能力感到无比惊讶。 |
| D | 最大的谜团之一是幼鸟是如何在没有父母引导的情况下找到传统越冬之地的。成年的鸟类很少带领幼鸟一起迁徙，雏鸟甚至很少或者从没见过其父母。以布谷鸟（杜鹃）为例，它们将蛋产在其它鸟类的巢中，然后再也不会回去看望幼仔。让人惊讶的是，当小杜鹃在宿主家里长大后，它便会自己飞到其祖先在热带地区的越冬地，然后独自飞回北欧，寻找和自己同种类的配偶。这有力地说明了杜鹃能够从其父母那里继承内罝的迁徙路线图和方向定位的能力，以及其他杜鹃鸟的外在长相的精神意象。然而，还没有人知道这究竟是怎么一回事。 |
| E | 越来越多的证据显示，鸟类能够利用太阳和星辰的方位来辨别方向。同时，它们似乎还能侦测地球磁场，这可能是由于鸟类脑部具有微小的磁性晶体的缘故。不过，真正的导航还需要对位置和时间的认知，特别是在迷路的时候。实验表明，当鸟儿被带出数千英里，跨越陌生的大陆板块之后，它们仍能迅速地回到自己的巢址。这种惊人的能力是对大量复杂的线索进行精密计算的结果，包括天生的夜空星图和地球磁场的拉力。鸟类是如何运用它们的“工具”的，我们还不得而知，但有一点是显而易见的：它们用比人类更高级的感官知觉来观察这个世界。大部分幼鸟在夜间进行迁徙，并通过日落的位置辨别方位。但是，当它们观察日落时，似乎还能观测到日落带来的偏极光，从而矫正它们的方位。夜间飞行还有其他好处。鸟类可以避开昼行食肉动物，并减少温暖日照下长时期飞行带来的脱水危险。此外，夜间的空气通常较为凉爽，很少有空气湍流，这有利于持续稳定的飞行。 |
| F | 然而，所有的旅程都暗含着危险，要想安全到达，其中一个要诀就是在正确的时间出发。这意味着要能准确地预测天气，并能合理地利用风向。鸟类从出生伊始就精通此道了。实验室测试还发现，有些鸟类甚至能够辨别出房间中天花板和地面之间气压的细微差别。通常，鸟类在有明显征兆前就能感应到即将发生的天气变化。灰头麦鸡，一种生活在草原的鸟类，能够在寒流到来前从荷兰向西飞到不列颠群岛、法国和西班牙。当地表结冰时，它们可能会饿死在冰雪消融之前，鸟儿们会再回到荷兰，它们是通过气压变化来预测天气转变的。 |
| G | 以威尔士马恩岛海鸥为例，它们被带到美国，然后再被释放，但是，在宣布被释放的消息之前，它们就已经飞回自己的住所一一彭布罗克郡海岸线外的斯科克霍尔姆（Skokholm）岛了！相反地，每个秋天都会有少量的北美鸟类被快速移动的西尾风刮到大西洋的另一边。它们不仅安全地到达了欧洲，而且越来越多的证据显示，其中一些可能还和欧洲候鸟们一起去了阳光充沛的非洲地区过冬，然后才在次年春天飞回北美。 |
题号定位词文中对应点题目解析
14 Design features that enable them toperform such amazing feats A段第一句A段开门见山提出鸟类特有的结构特征支持它们迁徙。之后就细化介绍了它们的特殊结构。
是个典型总分结构。所以第一句就是主题句，
因此，本题答案为iv。
15 Fundamental reason that birds migrate B段第一句B段开始提出了本段主题，之后给出了迁徙原因的解释。
因此，本题答案为 v。
16 Puzzling fact; much further C段第一句C段也是直接提出主题，然后用例子进行解释的结构。C段提出了鸟类飞到更远的地方过冬令人不解，接着用英国的燕子和北极燕鸥和水禽的迁徙例子来具体说明了人们的惊讶。
Puzzling对应答案中的unexplained;much further对应答案中rejection of closer
因此，本题答案为 ii。
17 Greatest mysteries; how young birds D段第一句D段第一句是主题句，整段接着用杜鹃的例子来具体化了此疑问。
Young bird体现了答案中的lack of teaching
因此，本题答案为 x。
18 Mounting evidence; birds use thepositions; to obtain compass direction; detect the earth’s magnetic field E段第一句第二句E段第一句提出了鸟类使用太阳和星星辨别方向有很多证据。第二句说同时鸟类似乎还可以预测地球磁场。这都在说鸟儿怎么飞。
因此，本题答案为 vii。
19 Setting off at the right time F段第一句F段第一句话提出安全飞行需要找到最好的出发的时间，第二句说那意味着要正确的天气预测，利用风向。也就是说第二句只是说明如何找到好的出发时间，说要iii 不能选。
因此，本题答案为 I。
20 One instance; are blown across;fast-moving westerly tail winds; arrive safely G段第一句和第二句和第三句。G段第一句说威尔士马恩岛海鸥是一个例子(那说明是承接上文的例子，而上面一段说的是正确预测天气和利用风向来找到好的飞行时间)。所以这要么是预测天气成功，要么是利用风向成功。后面第二句说到了西尾风。第三句说不仅成功，还飞去了非洲。
因此，本题答案为 viii。
21 Many birds journey much further thanwould be necessary just to find food C段第一句C段第一句明确提到许多鸟类的迁徙旅程远远长于它们为了寻找食物和好天气所必需飞行的距离。这也是C段的主题句。
因此，本题答案为 A。
22 Traveling at night; other benefits;danger of dehydration E段第九十两句E段接近结尾的第九十两句非常明确的提到了夜间飞行的好处：避免天敌和脱水。
因此，本题答案为C。
其它选项B在文中没有提到和家人一起飞行;D也没有提到，文章只是在第E段提到的是鸟类有比人类更高级的感官知觉they see theworld with a superior sensory perception to ours。E也没有在文中明确提出，并且一般有绝对词的答案可以率先排除。
23 One of the greatest mysteries; withoutparental guidance; a familiar example is that of the cuckoo D段第一句话和第三句话先用cuckoo定位到D段。
Cuckoo是该段主题幼鸟依靠自己迁徙到越冬之地的迷思的一个例子。
提干部分是对D段第一句话的paraphrase。
因此，本题答案是文中的parentalguidance。
24 Mounting evidence; position of sun andstars to obtain compass directions E段第一句话用tell direction和by observing the sun and the stars定位到E段第一句话。
因此，本题答案是文中的compass。
25 Traveling at night; other benefits;daytime predators are avoided E段第九十两句通过第22题其实已经可以直接做出这个题了。E段接近结尾的第九十两句非常明确的提到了夜间飞行的好处：避免天敌和脱水。
因此，本题答案为predators。
26 React to weather changes before there isany visible sign of them F段第四句用laboratory tests; detect weather定位到本句。
因此，本题答案为visible。
答案：
14.iv 15.v 16.ii 17.x 18.vii 19.i 20.viii 21.A
22.C 23. parental guidance 24. compass 25. predators 26. visible
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