GWD-9-Q33 to GWD-9-Q36:

Scientists studying the physiology

of dinosaurs have long debated whether

dinosaurs were warm- or cold-blooded.

Line Those who suspect they were warm-

(5) blooded point out that dinosaur bone

is generally fibro-lamellar in nature;

because fibro-lamellar bone is formed

quickly, the bone fibrils, or filaments, are

laid down haphazardly. Consistent with

(10) their rapid growth rate, warm-blooded

animals, such as birds and mammals,

tend to produce fibro-lamellar bone,

whereas reptiles, which are slowgrowing

and cold-blooded, generally

(15) produce bone in which fibrils are laid

down parallel to each other. Moreover,

like the bone of birds and mammals,

dinosaur bone tends to be highly

vascularized, or filled with blood

(20) vessels. These characteristics,

first recognized in the 1930’s,

were documented in the 1960’s by

de Ricqlès, who found highly vascularized,

fibro-lamellar bone in several

(25) groups of dinosaurs. In the 1970’s,

Bakker cited these characteristics as

evidence for the warm-bloodedness of

dinosaurs. Although de Ricqlès urged

caution, arguing for an intermediate type

(30) of dinosaur physiology, a generation of

paleontologists has come to believe

that dinosaur bone is mammalianlike.

In the 1980’s, however, Bakker’s

contention began to be questioned, as a

(35) number of scientists found growth rings

in the bones of various dinosaurs that

are much like those in modern reptiles.

Bone growth in reptiles is periodic in

nature, producing a series of concentric

(40) rings in the bone, not unlike the growth

rings of a tree. Recently, Chinsamy

investigated the bones of two dinosaurs

from the early Jurassic period

(208-187 million years ago), and found

(45) that these bones also had growth rings;

however, they were also partially fibrolamellar

in nature. Chinsamy’s work

raises a question central to the debate

over dinosaur physiology: did dino-

(50) saurs form fibro-lamellar bone because

of an innately high metabolic rate associated

with warm-bloodedness or

because of periods of unusually fast

growth that occurred under favorable

(55) environmental conditions? (Although

modern reptiles generally do not form

fibro-lamellar bone, juvenile crocodiles

raised under optimal environmental

conditions do.) This question remains

(60) unanswered; indeed, taking all the evidence

into account, one cannot make

a definitive statement about dinosaur

physiology on the basis of dinosaur

bone. It may be that dinosaurs had an

(65) intermediate pattern of bone structure

because their physiology was neither

typically reptilian, mammalian, nor avian.

GWD-9-Q36:

The author of the passage mentions bone growth patterns in juvenile crocodiles most

likely in order to

A. provide support for the argument that reptiles are not related to dinosaurs

B. undermine the claim that most reptiles are slow-growing

C. offer an explanation as to why juvenile crocodiles differ from most modern

reptiles

D. suggest the juvenile crocodiles have a type of physiology intermediate between

that of mammals and that of reptiles

E. suggest that the presence of fibro-lamellar bone does not resolve the debate over

请教，我实在不知道怎样推出E答案（正确答案给的是E），我没思路，或许是没看懂

谢谢

Scientists studying the physiology of dinosaurs have long debated whether dinosaurs were warm- or cold-blooded. 研究恐龙生理结构的科学家们长期以来对于恐龙到底是冷血动物还是温血动物这个问题争论不休。

Line Those who suspect they were warm- (5) blooded point out that dinosaur bone is generally fibro-lamellar in nature; because fibro-lamellar bone is formed quickly, the bone fibrils, or filaments, are laid down haphazardly. 认为恐龙是温血动物的科学家指出，恐龙的骨头通常是成fibro薄片状的。因为fibro薄片状的骨头生长的很快，这些骨头纤维或者细丝都是随意生长的。

Consistent with (10) their rapid growth rate, warm-blooded animals, such as birds and mammals, tend to produce fibro-lamellar bone, whereas reptiles, which are slowgrowing and cold-blooded, generally (15) produce bone in which fibrils are laid down parallel to each other. 为了和快速生长的速度相一致，这些温血动物如鸟类和哺乳动物，往往长出fibro纤维状的骨头，但是生长较慢的冷血爬行动物，通常长出的骨头的纤维是彼此平行的。

Moreover, like the bone of birds and mammals, dinosaur bone tends to be highly vascularized, or filled with blood (20) vessels. 而且，与鸟和哺乳动物的骨头一样，恐龙的骨头往往是高度脉管化的，或者充满了血管。

These characteristics, first recognized in the 1930’s, were documented in the 1960’s by de Ricqlès, who found highly vascularized, fibro-lamellar bone in several (25) groups of dinosaurs. In the 1970’s, Bakker cited these characteristics as evidence for the warm-bloodedness of dinosaurs.这些在30年代首次确认的特征，由DR在60年代记录在案，DR在几个不同种群的恐龙中发现了高度脉管化，fibro纤维化的骨头。 70年代，B引用这些特征作为恐龙的温血动物的证据。

Although de Ricqlès urged caution, arguing for an intermediate type (30) of dinosaur physiology, a generation of paleontologists has come to believe that dinosaur bone is mammalianlike. 尽管DR提出了警告，认为从恐龙生理学的角度而言可能存在着中间类型，但是很多古生物学家开始相信恐龙的骨头是哺乳类的。

In the 1980’s, however, Bakker’s contention began to be questioned, as a (35) number of scientists found growth rings in the bones of various dinosaurs that are much like those in modern reptiles.但是到了80年代，B的学说开始被人们质疑，因为很多科学家发现不同种类的恐龙的骨头生长环和现代爬行动物的很相像。

Bone growth in reptiles is periodic in nature, producing a series of concentric (40) rings in the bone, not unlike the growth rings of a tree. 爬行动物的骨头生长是周期性的，产生了一系列的同心环，和树的年轮的增长是一样的。

Recently, Chinsamy investigated the bones of two dinosaurs from the early Jurassic period (208-187 million years ago), and found (45) that these bones also had growth rings; however, they were also partially fibrolamellar in nature. 最近，C调查了J时代早期的2只恐龙的骨头，发现这些骨头也有生长环；但是这些生长环也部分是fibro纤维状的。Chinsamy’s work raises a question central to the debate over dinosaur physiology: did dino- (50) saurs form fibro-lamellar bone because of an innately high metabolic rate associated with warm-bloodedness or because of periods of unusually fast growth that occurred under favorable (55) environmental conditions? (Although modern reptiles generally do not form fibro-lamellar bone, juvenile crocodiles raised under optimal environmental conditions do.) C的工作对恐龙生理学提出了一个关键性的问题：恐龙生长fibro纤维状的骨头是否是因为在适宜的环境中的反常快速生长阶段引起的？（尽管现在的爬行动物普遍上都没有fibro纤维状的骨头，但是幼年的鳄鱼在最佳的环境下会生长这样的骨头）

This question remains (60) unanswered; indeed, taking all the evidence into account, one cannot make a definitive statement about dinosaur physiology on the basis of dinosaur bone. It may be that dinosaurs had an (65) intermediate pattern of bone structure because their physiology was neither typically reptilian, mammalian, nor avian. 这个问题仍然没有得到解决，事实上，考虑到所有的证据，人们不能基于恐龙的骨头得到一个关于恐龙生理学的定论。有可能恐龙在骨的构造上存在着中间阶段，因为他们的骨头既不是典型的爬行类，哺乳类或者鸟类。