<求助>GWD5-36-这周就考了

miaoyin_tx

Q35 to Q37:

      Even more than mountainside slides

            of mud or snow, naturally occurring forest

            fires promote the survival of aspen trees.

Line     Aspens’ need for fire may seem illogical

  (5)      since aspens are particularly vulnerable

to fires; whereas the bark of most trees

consists of dead cells, the aspen’s bark

is a living, functioning tissue that—along

with the rest of the tree—succumbs quickly

(10)     to fire.

      The explanation is that each aspen,

while appearing to exist separately as

a single tree, is in fact only the stem or

shoot of a far larger organism.  A group

(15)     of thousands of aspens can actually

constitute a single organism, called a

clone, that shares an interconnected root

system and a unique set of genes.  Thus,

when one aspen—a single stem—dies,

(20)     the entire clone is affected.  While alive,

a stem sends hormones into the root

system to suppress formation of further

stems.  But when the stem dies, its

            hormone signal also ceases.  If a clone

(25)     loses many stems simultaneously, the

resulting hormonal imbalance triggers a

huge increase in new, rapidly growing

shoots that can outnumber the ones

destroyed. An aspen grove needs to

(30)     experience fire or some other disturbance

regularly, or it will fail to regenerate and

spread.  Instead, coniferous trees will

            invade the aspen grove’s borders and

increasingly block out sunlight needed by

the aspens.

Q36:

It can be inferred from the passage that when aspen groves experience a “disturbance” (line 30), such a disturbance

                        

leads to a hormonal imbalance within an aspen clone

provides soil conditions that are favorable for new shoots

thins out aspen groves that have become overly dense

suppresses the formation of too many new aspen stems

protects aspen groves by primarily destroying coniferous trees rather than aspens

这题的参考答案是A，不过偶对A有疑惑。偶对文章的理解是Because the stem of aspen dies, its hormone signal also ceasese...The resulting homonal imbalance triggers a lhuge increase in new, rapadily growing shoots than can outnumber the ones destroyed(文中第24-33行).因此推出aspen 需要用火或者其它的干扰来解决这个现象。所以hormone的不均衡是因，干扰是果。根据A答案，干扰是因，hermone不均是果。另外一个证据是，第31行，如果aspen不能被定期干扰一下，它就不能再生或是扩张。这符合C说的干扰会清理掉过密的aspen groves. 请NN们指点一下，是我理解错了? 我是选C。

free_rabbit

我读的是，因为被火烧了，所以荷尔蒙失调了，就会激发更多的生长出来。。

miaoyin_tx

以下是引用free_rabbit在2004-9-24 5:23:00的发言：

我读的是，因为被火烧了，所以荷尔蒙失调了，就会激发更多的生长出来。。

I think you are right. I got it. 多谢啦

Xandria

我怎么怎么读都读不出二楼说的意思来啊?

明显是hormone导致stem生长抑制, 当aspen死了, hormone不分泌了, 所以stem大量的生长, 需要火烧才可以啊?

请NN帮忙看看我理解的哪里有问题啊?

Xandria

我觉得这题应该是选D吧?

Xandria

NN救命啊!

wangyu73cn

明显是hormone导致stem生长抑制, 当aspen死了, hormone不分泌了, 所以stem大量的生长, 需要火烧才可以啊?

stem正常分泌hormone导致further stems生长抑制。当stem死了或发生扰动,其hormone不均衡了, 所以further stems大量生长。

Xandria

请版主再看看, 先谢了.

如果按照版主的说法, 那就应该是这种Disturbulance会使得Hormone数量下降, 进而解决imbalance的问题, 可是A说的是lead to imbalance啊?

wangyu73cn

以下是引用Xandria在2005-6-18 7:36:00的发言：

那就应该是这种Disturbulance会使得Hormone数量下降, 进而解决imbalance的问题, 可是A说的是lead to imbalance啊?

楼上再认真看看原句But when the stem dies, its hormone signal also ceases.  If a clone loses many stems simultaneously, the resulting hormonal imbalance。应该是这种Disturbulance会使得Hormone停止分泌，imbalance即指这种停止。

[此贴子已经被作者于2005-6-18 14:44:43编辑过]

sherryly

问一下,37题为啥不选D,分号后不是把most tree和aspeen做比较,指出两者不同吗?