As skies are filled with millions of migrating(迁徙)birds, European scientists say the seasonal wonder appears to be strange: The fatter the bird, the better it flies.
The results of their study led to a theory opposite to a central one of aerodynamics(空气动力学), which says that the power needed to fly increases with weight.
For birds, obviously, the cost of flying with heavy fat is much smaller than we used to think. Researchers found that red knot wading birds double their normal body weight of 100 grams before making their twice-a-year nonstop flight between the British Isles and the Russian Arctic. Distance: 5, 000 kilometers.
Another study in the magazine Nature measured the advantage of flying in an aerodynamic group which allows birds to save energy by flying smoothly and quietly in the lead bird’s air stream.
Flying in groups, their heart rates were 14.5 percent lower than flying alone, according to Henri, a French scientist. The findings help explain how birds plete difficult migrations. Researchers had thought that thinner, stronger birds would have the best chance to survive.
The first study suggests that building up fat to be burnt as fuel during the migration is worth more than the energy it takes to carry the additional weight.
In the study, researchers said their team studied the birds flown at different body weights during 28 simulated(模拟的)flights. They forced a small amount of special water into the birds’ bodies so that they could measure the amount of energy burnt during the flight.
60.A red knot wading bird of 100 grams will probably weigh before making its nonstop migrating flight.
A.50 grams B.100 grams C.150 grams D.200 grams
61.During their migrating flight, red knot wading birds can save energy by flying .
A.separately B.alone C.in groups D.in pairs
62.A red not wading bird has a better chance to survive during its migrating flight.
A.stronger B.weaker C.thinner D.fatter
63.The best title for this passage may probably be .
A.Birds Thin Down For Journey B.Birds Fatten Up For Journey
C.How Birds Build Up Fat For Journey D.How Birds Burn Energy For Journey60--63 DCDB
网友回答
(答案→)60--63 DCDB
解析：
60．解析：这是一道计算题。根据第三段中的Researchers found that red knot wading birds double their normal body weight of 100 grams before making their twice-a-year nonstop flight between the British Isles and the Russian Arctic.可计算出在进行不停顿的迁徙飞行，一只red knot wading bird可能重200克。double their normal body weight of 100 grams表示“它们正常体重100克的两倍”，即200克。
61．解析：这是一道细节题。第四段中的Another study in the magazine Nature measured the advantage of flying in an aerodynamic group which allows birds to save energy by flying smoothly and quietly in the lead bird’s air stream.说明red knot wading birds以一群鸟一起飞行的方式进行飞行时能够节省能量。
62．解析：这是一道细节题。从第五段中的Researchers had thought that thinner, stronger birds would have the best chance to survive.可以看出，比较肥胖的red knot wading birds在迁徙飞行中更有机会存活。句子的谓语是虚拟语气，说明研究者原先认为越瘦越强壮的red knot wading birds存活的机会越大，而实际情况与此相反。
63．解析：这是一道标题选择题。这篇短文报道了对red knot wading birds迁徙飞行的研究，研究表明因为red knot wading birds在迁徙过程中消耗大量能量，所以比较肥胖的red knot wading birds越有在迁徙飞行中存活的机会，因此这篇短文的题目应是：Birds Fatten Up For Journey。