prep1-Essay15 快考试了，全部做错，请NN指点

mingminglous

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(冬眠,隐匿).  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 "complacentrings 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   
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.-我选C，从第一段句尾知会表现相同，但是最后一段句尾又说不同树种表现也会不同，所以综合两个我选了C，但答案是A，不理解，觉得没C全面
(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  
In the highlighted text, "uncertainties" refers to的

(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 -答案选E，但是我错选了C，感觉都是说年轮和气候的关系，跟树龄没关系吧

Question #52.  341-04    C

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
答案选C，我选B，我认为段首先提出树龄法这个东西，然后阐述这个原理，第2段用however否定其准确性啊。

还有4天就考试了 这篇阅读我全部做错，而且看了答案还是不能理解，期望牛牛解答，感激不尽！

songxuebest

第二题
“And trees in extremely dry regions may go a year or two without adding any rings, thereby introducing uncertainties into the count” 说 干旱地区的树 可能有一两年不长年轮   
答案说：ring和age的紧密关系被破坏了，正好是这句话的解释。
你选的答案是说：有一些种类的树blablabla~ 可是文章没有提到树的种类的问题

（一点见解）

mingminglous

恩，这个可以理解了，谢谢楼上~

coffee0921

beatthegmat上的关于Q50的解释：

Question 1:

The correct answer must be choice A.

If we have two trees that are from the same area, then of course the climate would have been the same in any given year. (It would be bizarre if we had significantly different climates at the same time in the same place).

So, for two trees from the same area, the rings corresponding to overlapping years would, according to the passage, undoubtedly exhibit similar patterns.

For choice B, note that the passage never asserts that legions of trees are necessary to arrive at conclusions about past climatic conditions. If we have only one tree, of course it is less convincing than if we have many (as always, a larger sample size provides a more solid foundation for arriving at confident conclusions). However, based on the explanation in the passage, there is no reason to think that an expert would require multiple trees to read off past climate conditions; the method described did not in any way depend on some sort of comparison of tree rings in multiple trees.

(Govi, choice D is wrong--the rings may be complacent if the two trees are in an area with a lot of groundwater).

saharaa

第一题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?

根据“different, but overlapping, ages”定位在第一段最后一句Often, ring patterns of dead trees of different, but overlapping, ages can be correlated to provide an extended index of past climate conditions.

关键在于理解can be correlated 。。两个不同的集合，只有存在交集的时候才可以相互联系起来（can be correlated）。不同树龄树的年轮只有在overlapping years 显示出相近的年轮exhibit similar patterns才可以相互联系起来，以推测当时的气候。所以选A。

(A) The rings corresponding to the overlapping years would often exhibit similar patterns.