[求助]prep test 1 - essay 15 急

greecechii

Test1-Essay #15. 341 (23562-!-item-!-188;#058&00341-00)

Dendrochronology, the study of tree-ring records to glean information about the past, is possible because each year a tree adds a new layer of wood between the existing wood and the bark. In temperate and subpolar climates, cells added at the growing season's start are large and thin-walled, but later the new cells that develop are smaller and thick-walled; the growing season is followed by a period of dormancy. When a tree trunk is viewed in cross section, a boundary line is normally visible between the small-celled wood added at the end of the growing season in the previous year and the large-celled spring wood of the following year's growing season. The annual growth pattern appears as a series of larger and larger rings. In wet years rings are broad; during drought years they are narrow, since the trees grow less. Often, ring patterns of dead trees of different, but overlapping, ages can be correlated to provide an extended index of past climate conditions.

However, trees that grew in areas with a steady supply of groundwater show little variation in ring width from year to year; these "complacent" rings tell nothing about changes in climate. And trees in extremely dry regions may go a year or two without adding any rings, thereby introducing uncertainties into the count. Certain species sometimes add more than one ring in a single year, when growth halts temporarily and then starts again.

Question #50. 341-02 (23608-!-item-!-188;#058&000341-02)

The passage suggests which of the following about the ring patterns of two trees that grew in the same area and that were of different, but overlapping, ages?

(A) The rings corresponding to the overlapping years would often exhibit similar patterns.
(B) The rings corresponding to the years in which only one of the trees was alive would not reliably indicate the climate conditions of those years.
(C) The rings corresponding to the overlapping years would exhibit similar patterns only if the trees were of the same species.
(D) The rings corresponding to the overlapping years could not be complacent rings.
(E) The rings corresponding to the overlapping years would provide a more reliable index of dry climate conditions than of wet conditions.

Question #51. 341-03 (23654-!-item-!-188;#058&000341-03)

In the highlighted text, "uncertainties" refers to

(A) dendrochronologists' failure to consider the prevalence of erratic weather patterns
(B) inconsistencies introduced because of changes in methodology
(C) some tree species' tendency to deviate from the norm
(D) the lack of detectable variation in trees with complacent rings
(E) the lack of perfect correlation between the number of a tree's rings and its age

Question #52. 341-04 (23700-!-item-!-188;#058&000341-04)

The passage is primarily concerned with

(A) evaluating the effect of climate on the growth of trees of different species
(B) questioning the validity of a method used to study tree-ring records
(C) explaining how climatic conditions can be deduced from tree-ring patterns
(D) outlining the relation between tree size and cell structure within the tree
(E) tracing the development of a scientific method of analyzing tree-ring patterns

我想问50题为什麽答案是A?
有人能帮忙解释吗?
谢谢~~

[此贴子已经被作者于2007-8-24 1:25:34编辑过]

chasemylove

定位在第一段的最后一句话，改写

greecechii

谢谢你,我知道定位是在第一段的最后一句话,但是为什麽会suggests "The rings corresponding to the overlapping years would often exhibit similar patterns." ?

可以帮忙解释这句话的意思吗? " Often, ring patterns of dead trees of different, but overlapping, ages can be correlated to provide an extended index of past climate conditions. "

不胜感激~~~

[此贴子已经被作者于2007-8-24 1:27:37编辑过]

nuj_am

我也为这个迷糊了半天了,现在试着解释一下吧,抛砖引玉.

Often, ring patterns of dead trees of different, but overlapping, ages can be correlated to provide an extended index of past climate conditions.

因为这是个infer题,所以我们得适当做一下推理.

有两棵树a和b, 比如a是10岁, b是13岁, a是2001年生得, b是2010年生的.

那么b得第一岁也就是第一个年轮和a得第十岁重合,那么他们两个年轮应该有相似得地方.这就是指这二者有different but overlapping age.

然后科学家通过定位到他们相同得这个2010年就可以通过a得年轮推出2001-2010年得气候,也可以通过b退出2010-2022年得气候.这就解释了to provide an extended index of past climate conditions.

这题有点像CR的assuption题, 我们得做一个假设, 科学家是怎么通过different but overlapping age去extend index呢?

那就是重合得年份, a和b得年轮得是一样的!

kaijen

Question #50. 341-02 (23608-!-item-!-188;#058&000341-02)

The passage suggests which of the following about the ring patterns of two trees that grew in the same area and that were of different, but overlapping, ages?

(A) The rings corresponding to the overlapping years would often exhibit similar patterns.
(B) The rings corresponding to the years in which only one of the trees was alive would not reliably indicate the climate conditions of those years.
(C) The rings corresponding to the overlapping years would exhibit similar patterns only if the trees were of the same species.
(D) The rings corresponding to the overlapping years could not be complacent rings.
(E) The rings corresponding to the overlapping years would provide a more reliable index of dry climate conditions than of wet conditions.

(D)這個答案要如何排除呀?
因為第一段末說 ring patterns of dead trees of different, but overlapping, ages 可以用來提供氣候狀況
第二段一開始又說 complacent rings 無法用來得知氣候的變遷
是不是就可以推得(D)的答案?

angelazhao1010

同楼上~