The fossil remains残骸，遗迹 of the first flying vertebrates, the pterosaurs（P）翼龙, have intrigued paleontologists古生物学家 for more than two centuries. 提出第一个问题：如何飞How such large creatures, which weighed in some cases as much as a piloted hang-glider有人驾驶的滑翔机 (hang-glider: n. 悬挂式滑翔机) and had wingspans from 8 to 12 meters, solved the problems of powered flight主动飞行, and 提出第二个问题：分类exactly what these creatures were—reptiles or birds—are among the questions scientists have puzzled over.
回答了第二个问题：爬行动物，与鸟对比Perhaps the least controversial assertion*1 about the pterosaurs is that they were reptiles*1D. Their skulls头骨, pelvises, and hind feet are reptilian. 最重要的论据The anatomy of their wings*3C suggests that they did not evolve into the class of birds鸟纲. 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*5A（不完全折叠，只能算bend，不能算fold） along each side of the animal’s body.
像鸟的地方是由别的原因导致的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, 不同之处however, these bones are reinforced more massively by internal struts.
像鸟的地方是由别的原因导致的Although scales鳞片 typically cover reptiles, the pterosaurs probably had hairy coats. T. H. Huxley（H） 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流线型 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（+for H）.
解决第一个问题，怎么飞的问题：三个理论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*2*7A浪尖. （列举） Each hypothesis has its difficulties*2B（-）. 解释缺点The 理论一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 理论二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. 理论三The wind that made such waves however, might have been too strong for the pterosaurs to control their flight once airborne.
1. It can be inferred from the passage that scientists now generally agree*1 that the直接事实题（很简单）
(A) enormous wingspan of the pterosaurs enabled them to fly great distances
(B) structure of the skeleton of the pterosaurs suggests a close evolutionary relationship to bats
(C) fossil remains of the pterosaurs reveal how they solved the problem of powered flight
(D) pterosaurs were reptiles*1D（D）
(E) pterosaurs walked on all fours
2. The author views the idea that the pterosaurs became airborne by rising into light winds created by waves*2（最后一段） as态度题
(A) revolutionary（+）
(B) unlikely*2B不可能（-）
(C) unassailable无懈可击（+）
(D) probable（+）（B）
(E) outdated过时（-）
3. According to the passage, the skeleton of a pterosaur can be distinguished（第二段，强对比） from that of a bird by the直接事实题
(A) size of its wingspan
(B) presence of hollow spaces in its bones
(C) anatomic origin of its wing strut*3C
(D) presence of hooklike projections on its hind feet（C）
(E) location of the shoulder joint joining the wing to its body
责任编辑：虫虫
