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标题: 求教一道阅读题 [打印本页]

作者: clear0127 时间: 2014-8-9 09:48
标题: 求教一道阅读题
The fossil remains of the first flying vertebrates, the pterosaurs, have intrigued paleontologists for more than two centuries. How such large creatures, which weighed in some cases as much as a piloted hang-glider and had wingspans from 8 to 12 meters, solved the problems of powered flight, and exactly what these creatures were—reptiles or birds—are among the questions scientists have puzzled over.

Perhaps the least controversial assertion about the pterosaurs is that they were reptiles. Their skulls, pelvises, and hind feet are reptilian. The anatomy of their wings suggests that they did not evolve into the class of birds. In pterosaurs a greatly elongated fourth finger of each forelimb supported a wing-like membrane. The other fingers were short and reptilian, with sharp claws. In birds the second finger is the principal strut of the wing, which consists primarily of feathers. If the pterosaurs walked on all fours, the three short fingers may have been employed for grasping. When a pterosaur walked or remained stationary, the fourth finger, and with it the wing, could only turn upward in an extended inverted V-shape along each side of the animal’s body.

The pterosaurs resembled both birds and bats in their overall structure and proportions. This is not surprising because the design of any flying vertebrate is subject to aerodynamic constraints. Both the pterosaurs and the birds have hollow bones, a feature that represents a savings in weight. In the birds, however, these bones are reinforced more massively by internal struts.

Although scales typically cover reptiles, the pterosaurs probably had hairy coats. T. H. Huxley reasoned that flying vertebrates must have been warm-blooded because flying implies a high rate of metabolism, which in turn implies a high internal temperature. Huxley speculated that a coat of hair would insulate against loss of body heat and might streamline the body to reduce drag in flight. The recent discovery of a pterosaur specimen covered in long, dense, and relatively thick hairlike fossil material was the first clear evidence that his reasoning was correct.

Efforts to explain how the pterosaurs became airborne have led to suggestions that they launched themselves by jumping from cliffs, by dropping from trees, or even by rising into light winds from the crests of waves. Each hypothesis has its difficulties. The first wrongly assumes that the pterosaurs’ hind feet resembled a bat’s and could serve as hooks by which the animal could hang in preparation for flight. The second hypothesis seems unlikely because large pterosaurs could not have landed in trees without damaging their wings. The third calls for high waves to channel updrafts. The wind that made such waves however, might have been too strong for the pterosaurs to control their flight once airborne.

7. It can be inferred from the passage that some scientists believe that pterosaurs
(A) lived near large bodies of water
(B) had sharp teeth for tearing food
(C) were attacked and eaten by larger reptiles
(D) had longer tails than many birds
(E) consumed twice their weight daily to maintain their body temperature
这道细节题我死也没找到啊

作者: 坏小子哈哈 时间: 2014-8-13 10:35
我也是没找到

作者: williamruan3 时间: 2014-8-13 20:36
最后一段的第二行
or even by rising into light winds from the crests of waves.
crests of waves 指的是波浪的波峰，说明它居住的环境周围有水系.. 而问题中其他的选项都没提到= =
所以貌似就是A

作者: clear0127 时间: 2014-8-14 21:03

williamruan3 发表于 2014-8-13 20:36
最后一段的第二行
or even by rising into light winds from the crests of waves.
crests of waves 指的是 ...

懂了，多谢！！

作者: ashlyzhu 时间: 2014-8-15 16:36

williamruan3 发表于 2014-8-13 20:36
最后一段的第二行
or even by rising into light winds from the crests of waves.
crests of waves 指的是 ...

by rising into light winds from the crests of waves.这里的waves 应该指的的是顺着风的波浪飞行吧。和水没有关系吧。从最后两句也能看出来：the third calls for high waves to channel updrafts. the wind that made such waves however, might have been too strong for the pterosaurs to control their flight once airbone.
我也找不到答案。。希望有人来给出具体解释

作者: williamruan3 时间: 2014-8-16 09:26

ashlyzhu 发表于 2014-8-15 16:36
by rising into light winds from the crests of waves.这里的waves 应该指的的是顺着风的波浪飞行吧。和 ...

我当时也觉得模棱两可..可能要根据选项来合理猜断了..只有A说的比较泛泛，不容易出大错误哈哈

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