题目内容
15.Anyone watching the autumn sky knows that migrating birds fly in a V formation,but scientists have long debated why.A new study finds that these big-winged birds carefully position their wingtips and flap (拍动) at the same rate,probably to catch the upward movement of air and save energy during flight.There are two reasons birds might fly in a V formation:It may make flight easier,or they're simply following the leader.Squadrons (中队) of planes can save fuel by flying in a V formation,and many scientists suspect that migrating birds do the same.Models that treated flapping birds like fixed-wing airplanes show that they probably save energy by drafting off each other,but currents created by airplanes are far more stable than those coming off of birds.
Just as aerodynamic (气动力) calculations would predict,the birds positioned themselves to fly just behind and to the side of the bird in front,timing their wing flaps to catch the uplifting eddies (涡流).When a bird flew directly behind another,the timing of the flapping reversed (相反) so that it could minimize the effects of the downdraft coming off the back of the bird's body."We didn't think this was possible,"Usherwood says,considering that the difficult achievement requires careful flight and incredible awareness of one's neighbors."Perhaps these big V formation birds can be thought of quite like an airplane with wings that go up and down."
The findings likely apply to other long-winged birds,such as pelicans and geese,Usherwood says.Smaller birds create more complex wakes (尾波) that would make drafting too difficult.The researchers did not attempt to calculate the birds'energy savings because the necessary physiological measurements would be too invasive for an endangered species.Previous studies show that birds can use 20% to 30% less energy while flying in a V.
Scientists do not know how the birds find that aerodynamic sweet spot,but they suspect that the animals line themselves up either by sight or by sensing air currents through their feathers.In future studies,the researchers will switch to more common birds,such as pigeons or geese.They plan to investigate how the animals decide who sets the course and the pace,and whether a mistake made by the leader can ripple through the rest of the flock to cause traffic jams.
59.The author takes squadrons of planes for example to showA.
A.birds may save energy by flying in a V formation
B.birds fly in a V formation for many more reasons
C.planes flying in a V formation follow the leader
D.planes flying in a V formation are more economical
60.Why did Usherwood think it impossible for a bird to fly directly behind another?D
A.Because birds differ from airplanes in wings.
B.Because birds know nothing about aerodynamics.
C.Because birds could hardly create stable currents as planes.
D.Because birds have to overcome great difficulties when flying.
61.What is the scientists'attitude towards the findings mentioned in the passage?A
A.Cautious.
B.Contradictory.
C.Confident.
D.Critical.
62.What would the researchers do in their future studies about the birds?D
A.Calculate the birds'energy savings.
B.Apply the findings to smaller birds.
C.Find how the birds line themselves up.
D.Do research on more common birds.
分析 本文主要介绍了科学家们对迁徙候鸟为何飞成V字形进行了研究.
解答 59. 答案 A 细节理解题.根据第二段中"Squadrons(中队) of planes can save fuel by flying in a V formation,and many scientists suspect that migrating birds do the same."可知举飞机的例子是为了说明鸟飞成V形是为了节省能量,故选A项.
60. 答案 D 推理判断题.根据第三段中"When a bird flew directly behind another,the timing of the flapping reversed(相反) so that it could minimize the effects of the downdraft coming off the back of the bird?s body.‘We didn?t think this was possible,'"和第四段中"Smaller birds create more complex wakes(尾波) that would make drafting too difficult."可知鸟飞行时必须得克服阻力,故选D项.
61. 答案 A 态度观点题.根据文章出现的"many scientists suspect that migrating birds do the same…The researchers did not attempt to calculate the birds?energy savings…Previous studies show that birds can use 20% to 30% less energy while flying in a V."可知科学家对他们的研究用"怀疑""可能"来定位,所以说他们是谨慎的,故选A项.
62. 答案 D 细节理解题.根据最后一段中"In future studies,the researchers will switch to more common birds,such as pigeons or geese."可知将来科学家研究的中心可能会转移到普通鸟群身上,故选D项.
点评 科技类阅读理解题主要考查考生对书面语篇的整体领悟能力和接受及处理具体信息的能力.试题的取材,密切联系当前我国和世界经济、科技等方面的变化,有关数据的来源真实可信.因此科普知识类文章是每年的必考题.分析历年的科普类文章我们不难发现以下特点:
1、文章逻辑性强,条理清楚,语法结构简单,用语通俗.
2、文章内容注重科技领域的新发现.内容新颖,从而使文章显得陌生,内容抽象复杂.
3、命题方面注意对具体细节的准确理解和以之为依据的推理判断.
4、以人们的日常行为或饮食健康入手,探讨利弊,诠释过程,阐述概念.
A. | has turned into | B. | has been turned into | ||
C. | will turn into | D. | will be turned into |
-But I'm sure it won't interest ______.( )
A. | somebody | B. | anybody | C. | nobody | D. | everybody |
A. | The moment to hear the bad news | |
B. | Immediately he heard the bad news | |
C. | As soon as hearing the bad news | |
D. | On hear the bad news |
A. | or else | B. | therefore | C. | after all | D. | what's more |
A. | will be fixed | B. | doesn't fix | C. | is not fixed | D. | is fixed |