gwd-1-Q9 to Q12 wangyu gg你在吗

Over the last 150 years, large

       stretches of salmon habitat have

       been eliminated by human activity:

Line       mining, livestock grazing, timber

  (5)      harvesting, and agriculture as well

as recreational and urban devel-

opment.  S的居住地遭人类活动的破坏

The numerical effect is

obvious:  there are fewer salmon

in degraded regions than in pris-

(10)      tine ones; however, habitat loss

also has the potential to reduce

genetic diversity.  虽然很少生长在退化的地区，但是   生活地方的减少有明显的影响导致genetic diversity减少

This is most

evident in cases where it results

in the extinction of entire salmon

(15)      populations.  genetic diversity导致的最明显后果

Indeed, most

analysts believe that some kind

of environmental degradation

underlies the demise of many

extinct salmon populations. 环境退化构成salmon灭绝的基础

(20)      Although some rivers have

       been recolonized, the unique

       genes of the original populations

have been lost.  虽然环境有改善，但原始基因遗失

      Large-scale disturbances in

(25)      one locale also have the potential

to alter the genetic structure of

populations in neighboring areas,

even if those areas have pristine

habitats. 在某一地区大规模的骚动也会改变基因结构

Why?  Although the

(30)      homing instinct of salmon to their

natal stream is strong, a fraction

of the fish returning from the sea

       (rarely more than 15 percent)

stray and spawn in nearby

(35)    streams. 解释原因

Low levels of straying

are crucial, since the process

provides a source of novel

genes and a mechanism

      by which a location can be

(40)     repopulated should the fish

there disappear.  

Yet high rates

of straying can be problematic(-)

because misdirected fish may

interbreed with the existing stock

(45)      to such a degree that any local

adaptations that are present

become diluted.  少量没关系 大量就很有问题了

Straying

rates remain relatively low when

environmental conditions are

(50)      stable, but can increase dramati-

cally when streams suffer severe

disturbance.  disturbance 会引起大量的迷路

The 1980 volcanic

eruption of Mount Saint Helens,

for example, sent mud and debris

(55)      into several tributaries of the

Columbia River.  For the next

couple of years, steelhead trout

(a species included among the

salmonids) returning from the

(60)      sea to spawn were forced to

find alternative streams.  As

a consequence, their rates of

straying, initially 16 percent,

rose to more than 40 percent

(65)      overall.                                           举例，火山爆发引起的disturbance

      Although no one has quantified

changes in the rate of straying

as a result of the disturbances

caused by humans, there is no

(70)      reason to suspect that the effect

would be qualitatively different

than what was seen in the

aftermath of the laceType w:st="on">MountlaceType> laceName w:st="on">SaintlaceName>

Helens eruption.  人类的影响同样巨大

Such a dra-

(75)      matic increase in straying from

damaged areas to more pristine

streams results in substantial

gene flow, which can in turn lower

the overall fitness of subsequent

generations.    后果

L11和L25都用了also表示并列，但是我看了好久都看不懂他们分别和哪一部分的内容并列。

The numerical effect is obvious:  there are fewer salmon in degraded regions than in pris(10)      tine ones; however, habitat loss also has the potential to reduce genetic diversity.  
数量方面的效果是明显的：较少的salmon在环境退化地区。但是(不仅仅在数量方面如此)，生存环境的减少有可能导致genetic diversity的减少。

Large-scale disturbances in one locale also have the potential to alter the genetic structure of populations in neighboring areas, even if those areas have pristine habitats.
在某一地区大规模的扰动，(不仅仅影响该地区的salmon物种的基因结构，)也会改变邻近地区的salmon物种的基因结构。

谢谢gg 阅读能力真强的说

自愧远远比不上你

Q11:

According to the passage, human activity has had which of the following effects on salmon populations?

An increase in the size of salmon populations in some previously polluted rivers

A decline in the number of salmon in some rivers

A decrease in the number straying salmon in some rivers

A decrease in the gene flow between salmon populations that spawn in polluted streams and populations that spawn in pristine streams

the answer is B. 偶不确定是否是在第一段中的7-9行定位的？哪位NN指点一下啊，谢谢？

就是L7-9

可是7~9只是说了There are fewer salmon in degraded regions than in pristine ones.没有说明decline这个现象呀？

是不是有些不准确？

还是不明白，原文说The numerical effect is obvious:  there are fewer salmon

 in degraded regions than in pristine ones;

 in degraded regions than in pristine ones;

 只是说在退化的地方鱼比PRISTINE少，又没说总体少。

还有第9题目，答案选B，如下原文哪里提到 a common misunderstanding 了

Bcorrect a common misunderstanding about the behavior of salmon in response to environmental degradation caused by human activity

Bcorrect a common misunderstanding about the behavior of salmon in response to environmental degradation caused by human activity