A
Birds have many unique design features that enable them to perform such amazing feats of endurance. They are equipped with lightweight, hollow bones, intricately designed feathers providing both lift and thrust for rapid flight, navigation systems superior to any that man has developed, 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 respiratory systems have to perform efficiently during sustained flights at altitude, so they have a system of extracting oxygen from their lungs that far exceeds that of any other animal. During the later stages of the summer breeding season, when food is plentiful their bodies are able to accumulate considerable layers of fat, in order to provide sufficient energy for their long migratory flights.
B
The fundamental reason that birds migrate is 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 Arctic regions of the Northern Hemisphere, where food is abundant during the short growing season. Many species can tolerate cold temperatures if food is plentiful, but when food is not available they must migrate. However, intriguing questions remain.
C
One puzzling fact is that many birds journey much further than would be necessary just to find food and good weather. Nobody knows, for instance, why British swallows, which could presumably survive equally well if they spent the winter in equatorial Africa, instead fly several thousands of miles further to their preferred winter home in South Africa Cape Province. Another mystery involves the huge migrations performed by arctic terns and mud flat-feeding shorebirds that breed close to Polar Regions. In general, the further north a migrant species breeds, the farther south it spends the winter. For arctic terns this necessitates an annual round trip of 25,000 miles. Yet, en route to their final destination in far-flung southern latitudes, all these individuals overfly other areas of seemingly suitable habitat spanning two hemispheres. While we may not fully understand birds' reasons for going to particular places, we can marvel at their feats.
D
One of the greatest mysteries is how young birds know how to find the traditional wintering areas without parental guidance. Very few adults migrate with juveniles in tow, and youngsters may even have little or no inkling of their parents' appearance. A familiar example is that of the cuckoo, which lays its eggs in another species nest and never encounters its young again. It is mind boggling to consider that, once raised by its host species, the young cuckoo makes its own way to ancestral wintering grounds in the tropics before returning single-handed to northern Europe the next season to seek out a mate among its own kind. The obvious implication is that it inherits from its parents an inbuilt route map and direction-finding capability, as well as a mental image of what another cuckoo looks like. Yet nobody has the slightest idea as to how this is possible.
E
Mounting evidence has confirmed that birds use the positions of the sun and stars to obtain compass directions. They seem also to be able to detect the earth's magnetic field, probably due to having minute crystals of magnetite in the region of their brains. However, true navigation also requires an awareness of position and time, especially when lost. Experiments have shown that after being taken thousands of miles over an unfamiliar landmass, birds are still capable of returning rapidly to nest sites. Such phenomenal powers arc the product of computing a number of sophisticated cues, including an inborn map of the night sky and the pull of the earth's magnetic field. How the birds use their 'instruments’ remains unknown, but one thing is clear: they see the world with a superior sensory perception to ours. Most small birds migrate at night and take their direction from the position of the setting sun. However, as well as seeing the sun go down, they also seem to sec the plane of polarized light caused by it, which calibrates their compass. Traveling at night provides other benefits. Daytime predators are avoided and the danger of dehydration due to flying for long periods in warm, sunlit skies is reduced. Furthermore, at night the air is generally cool and less turbulent and so conducive to sustained, stable flight.
F
Nevertheless, all journeys involve considerable risk, and part of the skill in arriving safely is setting off at the right time. This means accurate weather forecasting, and utilizing favorable winds. Birds are adept at both, and, in laboratory tests, some have been shown to detect the minute difference in barometric pressure between the floor and ceiling of a room. Often birds react to weather changes before there is any visible sign of them. Lapwings, which feed on grassland, flee west from the Netherlands to the British Isles, France and Spain at the onset of a cold snap. When the ground surface freezes the birds could starve. Yet they return to Holland ahead of a thaw, their arrival linked to a pressure change presaging an improvement in the weather.
G
In one instance a Welsh Manx shearwater carried to America and released was back in its burrow on Skokholm Island, off the Pembrokeshire coast, one clay before a letter announcing its release! Conversely, each autumn a small number of North American birds arc blown across the Atlantic by fast-moving westerly tail winds. Not only do they arrive safely in Europe, but, based on ringing evidence, some make it back to North America the following spring, after probably spending the winter with European migrants in sunny African climes.
Questions 14-20
Reading passage 2 has seven paragraphs, A-G
Choose the correct heading for each paragraph from the list of headings below. Write
the correct number, i-x, in boxes 14-20 on your answer sheet.
List of headings
i. The best moment to migrate
ii. The unexplained rejection of closer feeding ground
iii. The influence of weather on the migration route
iv. Physical characteristics that allow birds 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 trouble of wind
ix. Contrast between long-distance migration and short-distance migration
x. Mysterious migration despite lack of teaching
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 and 22 on your answer sheet.
Which TWO of the following statements are true of bird migration?
A Birds often fly further than they need to.
B Birds traveling in family groups are safe.
C Birds flying at night need less water.
D Birds have much sharper eye-sight than humans.
E Only shorebirds are resistant to strong winds.
Questions 23-26
Complete the sentences below using NO MORE THAN TWO WORDS from the
passage.
Write your answers in boxes 23-26 on your answer sheet.
23 It is a great mystery that young birds like cuckoos can find their wintering grounds without ________.
24 Evidence shows birds can tell directions like a ________by observing the sun and the stars.
25 One advantage for birds flying at night is that they can avoid contact with ______.
26 Laboratory tests show that birds can detect weather without ________signs.
题目解析
14 Design features that enable them to perform 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 the positions; 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 than would 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 the world 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; without parental 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parental guidance。
24 Mounting evidence; position of sun and stars 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 is any 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。
Section3：The clipper races
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