Question

4．Scientists have never known for sure whether dinosaurs were warm-blooded animals，like mammals and birds，or cold-blooded，like reptiles and fish．A re cent study shows that in fact many dinosaurs might not have belonged to either category but instead have fallen somewhere in the middle．
Warm-blooded animals ha ve bodies that are able to make their own heat．Their body temperatures stay about the same whether it is hot or cold outside．Cold-blooded animals can not make their own heat，so their body temperatures depend on how warm the outside temperature is．Warm-blooded animals have much more active lifestyles than cold-blooded ones．
When scientists first discovered the bones of ancient dinosaurs in the 1800s，they were sure the huge creatures must have been slow．But as scientists found more bones of smaller，quicker dinosaurs，like Velociraptor，they realized that the creatures may have been much more active than they had thought．
A team of biologists began to examine．They knew that warm-blooded animals grow faster than cold-blooded ones．The researcher realized that they could determine whether a dinosaur had been warm-or cold-blooded by finding its growth rate．
The scientists examine the growth rings in bones from 21 different dinosaur species．The width of the growth rings showed how much the dinosaurs grew each year，much like the rings in the tree trunk do．
"Our results showed that dinosaurs had growth rates th at were actually not characteristic of warm-blooded or cold-blooded animals，"said Brian Enquist，a scientist on the research team．"They didn't act like mammals or birds，nor did they act like reptiles or fish．"Instead，dinosaurs fell somewhere in between．Scientists called the middle-of-the-road creatures"mesotherms"．
Being mesotherms gave dinosaurs many advantages．They were faster and stronger than reptiles that had to rely on the sun for warmth．Being somewhat cold-blooded had its benefits too．Cold-blooded animals burn energy more slowly．So they need much less food to l ive than warm-blooded animals．"It is doubtful that a lion the size of T-rex could eat enough to survive，"explains John Grady，another biologist on the research team．By being mesothermic，the dinosaurs could be both fast and big．
12．What is Paragraph 2 mainly about？C
A．The advantage of cold-blooded animals．
B．The disadvantages of warm-blooded animals．
C．The differences between warm-and cold-blooded animals．
D．The advantages of both warm-and cold-blooded animals．
13．It can be inferred that mesotherms growD．
A．as slowly as cold-blooded animals   
B．as fast as warm-blooded animals
C．slower than cold-blooded animals    
D．slower than warm-blooded animals
14．A lion is mentioned in the last paragraph to stress thatD．
A．dinosaurs moved very fast   
B．dinosaurs had to rely on the sun for warmth
C．dinosaurs are large animals 
D．dinosaurs needed less food to survive
15．The text is mainly aboutC．
A．how dinosaurs disappeared
B．the growth areas of dinosaurs
C．whether dinosaurs were warm or cold-blooded animals 
D．the appearance and behavior of dinosaurs．

Answer 1

分析 科学家一直都不确定恐龙到底是温血还是冷血动物，为此开展了一些研究 和调查．

解答 CDDC
12．C 推理题．根据第二段的一些句子，如Warm-blooded animals ha ve bodies that are able to make their own heat以及Cold-blooded animals can not make their own heat，得知，主要比较冷血和温血动物之间的一些差别，故选C．
13．D 细节题．文章里They knew that warm-blooded animals grow faster than cold-blooded ones告诉我们温血动物比冷血动物长的速度更快，再接合最后一句dinosaurs fell somewhere in between．Scientists called the middle-of-the-road creatures"mesotherms"．故选D．
14．D 细节题．在文章中Cold-blooded animals burn energy more slowly．So they need much less food to l ive than warm-blooded animals得知，冷血动物消耗能量缓慢，所以他们需要很少的食物来维持生存，狮子和恐龙都属于这类动物，故选D．
15．C 主旨题．根据文章第一段Scientists have never known for sure whether dinosaurs were warm-blooded animals，like mammals and birds，or cold-blooded，like reptiles and fish科学家一直都不确定恐龙到底是温血还是冷血动物，为此开展了一些研究 和调查，所以整个文章大意为选项C．

点评 本文是一篇科教类阅读，题目涉及多道细节理解题，推理判断题，主旨大意题，词义猜测题．做题时学生应仔细阅读原文，把握文章主要内容，联系文章上下文内容并结合所给选项含义，从中选出正确答案，一定要做到有理有据，切忌胡乱猜测