- UID
- 359053
- 在线时间
- 小时
- 注册时间
- 2008-7-17
- 最后登录
- 1970-1-1
- 主题
- 帖子
- 性别
- 保密
|
请教大家两道题，这是大全里的第四篇文章，有两道题不懂，红色的是正确答案。
对第四题，后来感觉到B很有可能是对的，但是没有找到具体的理由，只是一种感觉. Q7就完全没感觉了，好像5个选项都没找到在文中的定位，看着哪个都和原文无关，不知道是我太粗心了还是别的 。谢谢。
The fossil remainsof the first flying vertebrates, the pterosaurs, have intrigued paleontologistsfor more than two centuries. How such large creatures, which weighed in somecases as much as a piloted hang-glider (hang-glider: n. 悬挂式滑翔机) and had wingspans from 8 to 12meters, solved the problems of powered flight, and exactly what these creatureswere—reptiles or birds—are among the questions scientists have puzzled over.
Perhaps the leastcontroversial assertion about the pterosaurs is that they were reptiles. Theirskulls, pelvises, and hind feet are reptilian. The anatomy of their wings suggeststhat they did not evolve into the class of birds. In pterosaurs a greatlyelongated fourth finger of each forelimb supported a wing-like membrane. Theother fingers were short and reptilian, with sharp claws. In birds the secondfinger is the principal strut of the wing, which consists primarily offeathers. If the pterosaurs walked on all fours, the three short fingers mayhave been employed for grasping. When a pterosaur walked or remainedstationary, the fourth finger, and with it the wing, could only turn upward inan extended inverted V-shape along each side of the animal’s body.
The pterosaursresembled both birds and bats in their overall structure and proportions. Thisis not surprising because the design of any flying vertebrate is subject to aerodynamicconstraints. Both the pterosaurs and the birds have hollow bones, a featurethat represents a savings in weight. In the birds, however, these bones arereinforced more massively by internal struts.
Although scalestypically cover reptiles, the pterosaurs probably had hairy coats. T. H. Huxleyreasoned that flying vertebrates must have been warm-blooded because flyingimplies a high rate of metabolism, which in turn implies a high internaltemperature. Huxley speculated that a coat of hair would insulate against lossof body heat and might streamline the body to reduce drag in flight. The recentdiscovery of a pterosaur specimen covered in long, dense, and relatively thick hairlikefossil material was the first clear evidence that his reasoning was correct.
Efforts to explainhow the pterosaurs became airborne have led to suggestions that they launchedthemselves by jumping from cliffs, by dropping from trees, or even by risinginto 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 andcould serve as hooks by which the animal could hang in preparation for flight.The second hypothesis seems unlikely because large pterosaurs could not havelanded in trees without damaging their wings. The third calls for high waves tochannel updrafts. The wind that made such waves however, might have been toostrong for the pterosaurs to control their flight once airborne.
4. Theideas attributed to T. H. Huxley in the passage suggest that he would mostlikely agree with which of the following statements?
(A) An animal’sbrain size has little bearing on its ability to master complex behaviors.
(B) An animal’sappearance is often influenced by environmental requirements and physicalcapabilities.
(C) Animalswithin a given family group are unlikely to change their appearancedramatically over a period of time.
(D) The originof flight in vertebrates was an accidental development rather than the outcomeof specialization or adaptation.（B）
(E) The pterosaurs shouldbe classified as birds, not reptiles.
7. Itcan be inferred from the passage that some scientists believe that pterosaurs
(A) lived near large bodies ofwater
(B) had sharpteeth for tearing food
(C) wereattacked and eaten by larger reptiles
(D) had longertails than many birds（A）
(E) consumed twice theirweight daily to maintain their body temperature |
|
京公网安备11010202008513号 京ICP证101109号 京ICP备12012021号
发表于 2010-7-26 11:04:06
收藏
收藏
楼主
