新SAT官方指南阅读第十三篇全解析
新SAT官方指南阅读第十三篇全解析
This passage is adapted from Thor Hanson,Feathers.?2011by Thor Hanson.Scientists have long debated how the ancestors of birds evolved the ability to fly.The ground-up theory assumes they were fleet-footed ground dwellers that captured prey by leaping and flapping their upper
limbs.The tree-down theory assumes they were tree climbers that leapt and glided among
branches.
At field sites around the world,Ken Dial saw a pattern in how young pheasants,quail, tinamous,and other ground birds ran along behind their parents.“They jumped up like popcorn,”
he said,describing how they would flap their half-formed wings and take short hops into the air.
So when a group of graduate students challenged him to come up with new data on the age-old
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ground-up-tree-down debate,he designed a project to see what clues might lie in how baby game birds learned to fly.
Ken settled on the Chukar Partridge as a model species,but he might not have made his discovery without a key piece of advice from the local rancher in Montana who was supplying
him with birds.When the cowboy stopped by to see how things were going,Ken showed him his nice,tidy laboratory setup and explained how the birds’first hops and flights would be measured. 10
The rancher was incredulous.“He took one look and said,in pretty colorful language,‘What are those birds doing on the ground?They hate to be on the ground!Give them something to climb on!’”At first it seemed unnatural—ground birds don’t like the ground?But as he thought about it
Ken realized that all the species he’d watched in the wild preferred to rest on ledges,low branches, 15
or other elevated perches where they were safe from predators.They really only used the ground for feeding and traveling.So he brought in some hay bales for the Chukars to perch on and then
left his son in charge of feeding and data collection while he went away on a short work trip.
Barely a teenager at the time,young Terry Dial was visibly upset when his father got back.“I asked him how it went,”Ken recalled,“and he said,‘Terrible!The birds are cheating!’”Instead of flying up to their perches,the baby Chukars were using their legs.Time and again Terry had
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watched them run right up the side of a hay bale,flapping all the while.Ken dashed out to see for himself,and that was the“aha”moment.“The birds were using their wings and legs
cooperatively,”he told me,and that single observation opened up a world of possibilities.
Working together with Terry(who has since gone on to study animal locomotion),Ken came 25
up with a series of ingenious experiments,filming the birds as they raced up textured ramps tilted at increasing angles.As the incline increased,the partridges began to flap,but they angled their
wings differently from birds in flight.They aimed their flapping down and backward,using the
force not for lift but to keep their feet firmly pressed against the ramp.“It’s like the spoiler on the back of a race car,”he explained,which is a very apt analogy.In Formula One racing,spoilers are 30
the big aerodynamic fins that push the cars downward as they speed along,increasing traction and handling.The birds were doing the very same thing with their wings to help them scramble up
otherwise impossible slopes.
Ken called the technique WAIR,for wing-assisted incline running,and went on to document it in a wide range of species.It not only allowed young birds to climb vertical surfaces within the 35
first few weeks of life but also gave adults an energy-efficient alternative to flying.In the Chukar
experiments,adults regularly used WAIR to ascend ramps steeper than90degrees,essentially
running up the wall and onto the ceiling.
In an evolutionary context,WAIR takes on surprising explanatory powers.With one fell
swoop the Dials came up with a viable origin for the flapping flight stroke of birds(something
gliding animals don’t do and thus a shortcoming of the tree-down theory)and an aerodynamic 40
function for half-formed wings(one of the main drawbacks to the ground-up hypothesis).
21、Which choice best reflects the overall sequence of events in the passage?
A)An experiment is proposed but proves unworkable;a less ambitious experiment is attempted, and it yields data that give rise to a new set of questions.
B)A new discovery leads to reconsideration of a theory;a classic study is adapted,and the results are summarized.
C)An anomaly is observed and simulated experimentally;the results are compared with previous findings,and a novel hypothesis is proposed.
D)An unexpected finding arises during the early phase of a study;the study is modified in response to this finding,and the results are interpreted and evaluated
正确答案：D
分析：文章当中，作者提到：Ken Dial设计了一个实验，这个实验旨在通过观察幼鸟Chukars 学习飞行的过程观研究飞行进化过程；在实验过程中，Ken Dial发现Chukars配合使用翅膀和爪子的独特方式,于是他又补充设计了一些实验来研究这个观察的结果。经过补充实验，Ken Dial发现了一些意料之外的结果。
22、As used in line4,“challenged”most nearly means
A)dared.
B)required.
C)disputed with.
D)competed with.
正确答案：A
分析：文章当中提到，一群研究生向Ken Dial提出挑战，要开发一批关于Ground up和Tree down理论的新数据。Challenge和dare都表示挑战。
23、Which statement best captures Ken Dial’s central assumption in setting up his research?
A)The acquisition of flight in young birds sheds light on the acquisition of flight in their evolutionary ancestors.
B)The tendency of certain young birds to jump erratically is a somewhat recent evolved behavior.
C)Young birds in a controlled research setting are less likely than birds in the wild to require perches when at rest.
D)Ground-dwelling and tree-climbing predecessors to birds evolved in parallel.
正确答案：A
分析：Ken Dial原本设计的实验是搜集古老鸟类关于飞行进化的数据（new data on the age-old ground-up-tree-down debate）,结果他从幼鸟学习飞行的过程中去寻找线索（look for clues in how baby game birds learned to fly.）这样的策略表明：Ken Dial假设幼鸟飞行行为可以解释古老鸟类的飞行进化史。Shed light on的意识是：阐明，使……清晰地显出。
24、Which choice provides the best evidence for the answer to the previous question?
A)Lines1-2(“At field...parents”)
B)Lines3-6(“So when...fly”)
C)Lines9-10(“When...measured”)
D)Line13(“At first...the ground”)
正确答案：B
分析：见第23题解释。
25、In the second paragraph(lines7-17),the incident involving the local rancher mainly serves to
A)reveal Ken Dial’s motivation for undertaking his project.
B)underscore certain differences between laboratory and field research.
C)show how an unanticipated piece of information influenced Ken Dial’s research.
D)introduce a key contributor to the tree-down theory.
正确答案：C
分析：当一名农民观察Ken Dial的实验时，对于Chukars生活在地面这一点有怀疑，于是建议Dial要提供一些道具给幼鸟爬行。这一条重要建议使得Dial在他的试验中增添了一些干草。
26、After Ken Dial had his“‘aha’moment”(line22),he
A)tried to train the birds to fly to their perches.
B)studied videos to determine why the birds no longer hopped.
C)observed how the birds dealt with gradually steeper inclines.
D)consulted with other researchers who had studied Chukar Partridges.
正确答案：C
分析：在Ken Dial的“喜悦时刻”之后，他录制了这些鸟类爬上更加陡峭斜坡的画面（He
filmed the birds as they raced up textured ramps tilted at increasing angles）.
27、The passage identifies which of the following as a factor that facilitated the baby Chukars’traction on steep ramps?
A)The speed with which they climbed
B)The position of their flapping wings
C)The alternation of wing and foot movement
D)Their continual hopping motions
正确答案：B
分析：Ken Dial观察到：当Chukars在陡峭斜坡上时，他们开始拍打翅膀并且利用翅膀支撑使自己固定在斜坡之上（aimed their flapping down and backward,using the force…to keep their feet firmly pressed against the ramp）.说明翅膀是Chukars是在斜坡上的牵引力量。
28、As used in line33,“document”most nearly means
A)portray.
B)record.
C)publish.
D)process.
正确答案：B
分析：在33-34行，Ken Dial记录了很多物种都有WAIR的存在（WAIR是Dial的科学发现）。
29、What can reasonably be inferred about gliding animals from the passage?
A)Their young tend to hop along beside their parents instead of flying beside them.
B)Their method of locomotion is similar to that of ground birds.
C)They use the ground for feeding more often than for perching.
D)They do not use a flapping stroke to aid in climbing slopes.
正确答案：D
分析:在39-40行，作者提到，滑行动物不使用拍动翅膀的方式获得向上的动力。
30、Which choice provides the best evidence for the answer to the previous question?
A)Lines2-3(“They jumped...air”)
B)Lines15-16(“They really...traveling”)
C)Lines31-32(“The birds...slopes”)
D)Lines39-40(“something...theory”)正确答案：D
分析：见第29题解释。