GWD 5-37

Even more than mountainside slides of mud or snow, naturally occurring forest fires promote the survival of aspen trees. Aspens’ need for fire may seem illogical 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 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 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, 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 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 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.(35)

Q37:The author of the passage refers to “the bark of most trees” (line 6) most likely in order to emphasize the

Q35:

The primary purpose of the passage is to explain the

1. qualities that make a particular organism unique
2. evolutionary change undergone by a particular organism
3. reasons that a phenomenon benefits a particular organism
4. way in which two particular organisms compete for a resource
5. means by which a particular organism has been able to survive in a barren region

ANS: C   

Q36:

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

1. leads to a hormonal imbalance within an aspen clone
2. provides soil conditions that are favorable for new shoots
3. thins out aspen groves that have become overly dense
4. suppresses the formation of too many new aspen stems
5. protects aspen groves by primarily destroying coniferous trees rather than aspens

ANS: A   

为什么？

Aspen 对火的需要似乎有问题，因为aspens are vulnerable to fires。 然后他就解释了，大部分树的树皮都是死细胞，烧了也不怕，可是aspen 的树皮却是 a living, functioning tissue 并且和树的其他部分一起，一烧就死。

所以我觉得选A

Q35:

The primary purpose of the passage is to explain the

1. qualities that make a particular organism unique
2. evolutionary change undergone by a particular organism
3. reasons that a phenomenon benefits a particular organism
4. way in which two particular organisms compete for a resource
5. means by which a particular organism has been able to survive in a barren region

为什么不选E呢？

Q36:

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

1. leads to a hormonal imbalance within an aspen clone
2. provides soil conditions that are favorable for new shoots
3. thins out aspen groves that have become overly dense
4. suppresses the formation of too many new aspen stems
5. protects aspen groves by primarily destroying coniferous trees rather than aspens

我知道A是对的。为什么E会错呢？

谢谢

文章没有说a是生长在barren region。文章都是在说明火对a的生长有什么帮助。

An aspen grove needs to 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

这里的disturbance和fire是对上面的总结。就是a要经历disturbance才生长的更好。下面的coniferous trees可以看作一种disturbance。但是文章没有对它进行分析，实际上作者想表明这个coniferous trees对a的生长是有益的。E的意思与之相反。

啊。。。我竟然把意思都看反了！！

THX

那么请问D为什么有问题不对呢？？？？