GWD 1-25

xinfaxian

以下是引用scorpio0001在2005-2-24 17:52:00的发言：

1、 27题

我一开始这道题也选C，主要是我最初认为several weeks不是short term。但是，我觉得short term 或long term 是极度主观的感觉，况且此文中没有参照时间，所以不能说several weeks就是short term。但是下面一段话可以排除C选项，原因在于:生物钟的周期可以通过外界环境的改变而改变。可以推断，若实验室维持一个不变的（constant）环境，过不了多久，生物钟的周期就会改变。所以C的long term 是错误的。

This is not to suggest that the

(40)    period of this biological clock is

immutably fixed.  Biologists have

concluded that even though a

diatom does not rely on the envi-

ronment to keep time, environmental

(45)     factors—including changes in the

tide’s hydrostatic pressure, salin-

ity, mechanical agitation, and

temperature—can alter the period

of its biological clock according to

(50)     changes in the tidal cycle

继续讨论

分析的太有道理了。我一开始就是想不明白，为什么several weeks是短期的我也选了C,现在彻底搞定，谢谢mm.

xxiaoyan

请问一下：楼上所说的

原因在于:生物钟的周期可以通过外界环境的改变而改变。可以推断，若实验室维持一个不变的（constant）环境，过不了多久，生物钟的周期就会改变。所以C的long term 是错误的。

不明白这是啥意思，维持一个不变的环境，生物钟的周期怎么改变？    还是我的理解有误？

xiaoxiao很晕得说

wangyu73cn

我想，scorpio0001的意思是说，维持一个(可以改变周期的)不变的constant环境，过一段时间，周期就改变了。

xiangqinzh

顶

[此贴子已经被作者于2007-1-6 12:19:11编辑过]

xiangqinzh

关于25题选C 的理由

A commuter diatom has an unusu-      ad. 异乎寻常地(显著地,非常)

       ally accurate biological clock, a

consequence of the unrelenting     a. 不屈不挠的,不松懈的  

 

 (35)
                    environmental pressures to which

it is subjected; any diatoms that do

not burrow before the tide arrives

are washed away.

 

有准确的生物钟，是有因为经历的不屈不扰的压力的结果，取非：没有经过压力，那么生物钟就没有那么准确  ,所以正好是C想表达的意思

sunfu

以下是引用scorpio0001在2005-2-24 17:52:00的发言：

1、 27题

我一开始这道题也选C，主要是我最初认为several weeks不是short term。但是，我觉得short term 或long term 是极度主观的感觉，况且此文中没有参照时间，所以不能说several weeks就是short term。但是下面一段话可以排除C选项，原因在于:生物钟的周期可以通过外界环境的改变而改变。可以推断，若实验室维持一个不变的（constant）环境，过不了多久，生物钟的周期就会改变。所以C的long term 是错误的。

This is not to suggest that the

(40)    period of this biological clock is

immutably fixed.  Biologists have

concluded that even though a

diatom does not rely on the envi-

ronment to keep time, environmental

(45)     factors—including changes in the

tide’s hydrostatic pressure, salin-

ity, mechanical agitation, and

temperature—can alter the period

of its biological clock according to

(50)     changes in the tidal cycle

继续讨论

我觉得选C。你看27题的题目：

Q27:

According to the passage, the periodic behavior displayed by commuter diatoms under constant laboratory conditions is characterized by which of the following?

             

1. Greater unpredictability than the corresponding behavior under natural conditions
2. A consistent periodic schedule in the short term
3. No difference over the long term from the corresponding behavior under natural conditions
4. Initial variability caused by the constant conditions of the laboratory
5. Greater sensitivity to environmental factors than is the case under natural conditions

它问的是“周期性的行为”而不是“周期”，大家不要认为关键在于“短期”还是“长期”，关键在于实验室中的这个commuter diatoms 的行为与实验室外的比较。我把文章中有关的地方截下来，大家看看：

            ment.  However, when diatoms are

            observed under constant conditions

in a laboratory, they still display

periodic behavior, continuing to bur-

 (25)      row on schedule for several weeks.

This indicates that commuter diatoms,

rather than relying on environmental

cues to keep time, possess an inter-

nal pacemaker or biological clock

 (30)      that enables them to anticipate peri-

odic changes in the environment.

实验室环境下的diatoms还是表现出了周期性的行为，这个与C强调的重点——两种环境下行为比较——是相同的，文章并没有提到几周时间是short还是long，因此我们不能主观判定这件事，所以C是正解。

christy42728

1. The unusual accuracy that characterizes the commuter diatom’s biological clock is rare among intertidal species.
2. The commuter diatom’s biological clock is likely to be more accurate than the biological clock of a species that is subject to less intense environmental pressures

我觉得B C都有不妥之处，B好像没有明确说CD和其他的对比。C文章说unrelenting pressure 而答案less intense pressures一说恒定一说变小也不太对，到底比较之下选哪个？请指教

bbxiaos

再问这个25题，

C选项The commuter diatom’s biological clock is likely to be more accurate than the biological clock of a species that is subject to less intense environmental pressures。

这里的比较： to be more accurate than the biological clock of a species，apecies指的是什么呀，从文中的“

A commuter diatom has an unusu-

       ally accurate biological clock, a

consequence of the unrelenting

 (35)
                          environmental pressures to which it is subjected

也没看出来有拿commuter和哪个species相比较，还请大家帮忙看看！！

A commuter diatom has an unusu-

       ally accurate biological clock, a

consequence of the unrelenting

 (35)
                  environmental pressures to which it is subjected

也没看出来有拿commuter和哪个species相比较，还请大家帮忙看看！！

sch

我觉得选C。你看27题的题目：

Q27:

According to the passage, the periodic behavior displayed by commuter diatoms under constant laboratory conditions is characterized by which of the following?

             

1. Greater unpredictability than the corresponding behavior under natural conditions
2. A consistent periodic schedule in the short term
3. No difference over the long term from the corresponding behavior under natural conditions
4. Initial variability caused by the constant conditions of the laboratory
5. Greater sensitivity to environmental factors than is the case under natural conditions

它问的是“周期性的行为”而不是“周期”，大家不要认为关键在于“短期”还是“长期”，关键在于实验室中的这个commuter diatoms 的行为与实验室外的比较。我把文章中有关的地方截下来，大家看看：

            ment.  However, when diatoms are

            observed under constant conditions

in a laboratory, they still display

periodic behavior, continuing to bur-

 (25)      row on schedule for several weeks.

This indicates that commuter diatoms,

rather than relying on environmental

cues to keep time, possess an inter-

nal pacemaker or biological clock

 (30)      that enables them to anticipate peri-

odic changes in the environment.

实验室环境下的diatoms还是表现出了周期性的行为，这个与C强调的重点——两种环境下行为比较——是相同的，文章并没有提到几周时间是short还是long，因此我们不能主观判定这件事，所以C是正解。

＋＋＋＋＋＋＋＋＋＋＋＋＋＋＋＋＋＋＋＋＋＋＋＋＋＋＋＋＋＋＋＋＋＋＋＋

这位说得是正解。

文章前面是说，一些科学家怀疑diatom是通过周围环境，诸如温度水压等，感知tide变low了，所以露头了。 然后话题一转，however,通过实验室的恒定条件（温度水压等不变）的观测下，diatom还是到点就露头－－－－－－这说明了，diatom不是靠环境线索，而是靠得内部生物种来和环境变化保持pace的。

所以当题目问你： According to the passage, the periodic behavior displayed by commuter diatoms under constant laboratory conditions is characterized by which of the following?

在实验室恒定条件下，diatom显示出来的periodic行为要用什么来概括？

其实就是问你实验结果是什么？－－－－－－实验结果的中心思想就是“不变”，虽然外界环境和自然界不一样，但是diatom的到点起床行为保持“不变”。

所以，C中 no difference才是呼应。

sch

接着说：
文章一开始说：
。。。。。。。

文
章前面是说，一些科学家怀疑diatom是通过周围环境，诸如温度水压等，感知tide变low了，所以露头了。
然后话题一转，however,通过实验室的恒定条件（温度水压等不变）的观测下，diatom还是到点就露头－－－－－－这说明了，diatom不是靠
环境线索，而是靠得内部生物种来和环境变化保持pace的。

第一段其实就想说明，diatom用生物钟，而不是其它感知手段，按时起床的、

第二段呢，既然提到了生物种，第二段开始谈，影响生物钟周期的因素。

。。。。。。。。。。

所以27题问你实验室环境恒定的时候，diatom周期性行为说明了什么，只有去第一段找。