天山 3-25 这篇 很难！

createdream

  Researchers studying how genes control animal behavior have had

to deal with many uncertainties.  In

Line      the first place, most behaviors are

(5) governed by more than one gene, and until recently geneticists had no method for identifying the multiple genes involved.  In addition, even

when a single gene is found to control

(10) a behavior, researchers in different fields do not necessarily agree that it is a “behavioral gene.”  Neuroscientists, whose interest in genetic research is to understand the nervous system (which

(15) generates behavior), define the term broadly.  But ethologists— specialists in animal behavior — are interested

in evolution, so they define the term narrowly.  They insist that mutations in

(20) a behavioral gene must alter a specific normal behavior and not merely make the organism ill, so that the genetically induced behavioral change will provide variation that natural selection can act

(25) upon, possibly leading to the evolution of a new species.  For example, in the fruit fly, researchers have identified the gene Shaker, mutations in which cause flies to shake violently under

(30) anesthesia.  Since shaking is not healthy, ethologists do not consider Shaker a behavioral gene.  In con- trast, ethologists do consider the gene period (per), which controls the fruit

(35) fly’s circadian (24-hour) rhythm, a
behavioral gene because files with
mutated per genes are healthy; they
simply have different rhythms.

Q25：

The passage suggests that neuroscientists would most likely consider Shaker to be which of the following?

A. An example of a behavioral gene

B. One of multiple genes that control a single behavior

C. A gene that, when mutated, causes an alteration in a specific normal behavior without making the organism ill

D. A gene of interest to ethologists but of no interest to neuroscientists

E. A poor source of information about the nervous system.

ans. A

为何选A？ 文中并无任何提示呀！ 如何排除D，E 呢？

[此贴子已经被作者于2004-12-11 6:51:12编辑过]

concong

Line12－19

Neuroscientists,

whose interest in genetic research is to

understand the nervous system (which

(15) generates behavior), define the term

broadly. But ethologists—specialists

in animal behavior—are interested

in evolution, so they define the term

narrowly.

Line30-32

Since shaking is not

healthy, ethologists do not consider

Shaker a behavioral gene.

D. A gene of interest to ethologists but of no interest to neuroscientists

E. A poor source of information about the nervous system

文中都没有提到

createdream

好感谢 concong  mm ,  谁说你不是天使，我看就是      

有时真是当局者迷，走不出思维定式，一提醒就开窍了

题目是： The passage suggests that neuroscientists would most likely consider Shaker to be which of the following?   

啊，真是愚昧啊，没有理解more likely的比较对象！

我原来的理解是：neuroscientists 认为 Shaker   更可能是下面哪个选项？（比较对象是下面的5个选项）

正确的理解应该是：neuroscientists ( 比 ethologists) 更可能认为Shaker 是下面哪个选项？（ 比较对象是 neuroscientists  和 ethologists )

不知我这样理解和总结对不对呢？？

[此贴子已经被作者于2005-1-27 5:54:44编辑过]

concong

啊哦～说得偶都晕了，不过有一点有也是这样认为的，就是题目做了一种比较：neuroscientists 和ethologists

提干中提到Shaker，回文定位，文章中只直接讲到ethologists对shaker的看法，所以只能回到前面看两者的差异，感觉有点像取非的做法。

createdream

“文章中只直接讲到ethologists对shaker的看法，所以只能回到前面看两者的差异”

说得好！！

谢谢 concong  mm    

jessica628

Q27:
The primary purpose of the passage is to
A. summarize findings in an area of research
B. discuss different perspectives on a scientific question
C. outline the major questions in a scientific discipline
D. illustrate the usefulness of investigating a research topic
E. reconcile differences between two definitions of a term
Answer:b

能否讨论一下27 ? c 为何不对？

开头讲“many uncertainties", in the first place,....in addition,...如果说只是discuss different perspectives on a scientific question，岂不是前10行都没有用？我觉的文章的开头是很重要得。

个人觉得，尽管后面大讲区别，但是为主题服务。

wzhyan

三楼讲的很对

做这种中心题或主要内容的题目，总是觉得没把握

各有说法

比如27题，我也觉得应该是C，凭什么非是B呢，我同意楼上的意见，

但不知道为什么，第一页以后的几页都不能查看了

sensornet

C比B好，除了那个discipline。不过谁知道ets它们怎么定义这个词呢？

juningw

27题，确实C比B好。

偶原来选B，现改C。

scorp_w

25 同意2楼！