Prep Essay15

chipmunk

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

     

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.

请问A是怎么得出的呢？这里overlapping year是同一年的意思吗？

最后一段末尾 说 trees of certain species 一年里会长出 more than one ring, 如果这样，凭什么说 任意的两颗  树在同一年一定会show similar pattern。

Certain trees一年长 两道 年轮，Other trees 一年长 一道年轮，它们怎么会 show similar pattern?

难道我对pattern的理解有错吗？

kittycd

我觉得这道题目应该定位在第一段的最后一句。

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

一方面是因为overlapping这个关键词只出现在这一个地方，另一方面是因为整个第二段是在讲和第一段相反的一些情况，即根据tree rings不能得出past climate condition。

这道题我也做错了，选了E。当时只是简单的从选项中找了一个和这句话相近的答案。
现在想想A是有一定道理的。
注意题干和原文这句话的表达：
题干：the ring patterns of two trees that grew in the same area and
that were of different, but overlapping, ages?
原文：ring patterns of dead trees of
different, but overlapping, ages can be correlated to...
一个是two trees，另一个是dead trees。既然dead trees can be correlated，那two trees也应该能够correlated，而correlate有相互关联的意思，那说明two trees的ring patterns应该有similar之处，否则
是不能提供有关过去climate情况的有效信息。

个人拙见。

georgina1107

我也选的E 但我后面想了下 还是限定词不同

第一段末尾说的是ring patterns of dead trees of different, but overlapping, ages can be correlated to provide an extended index of past climate conditions.

但第2段 trees that grew in areas with a steady supply of groundwater 还是不同的trees

理由基本和LS差不多 想想是这样的 越能correlated

with二

偶也选E~
老外的解释：

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).

with二

看了老外的解释，偶觉得E不对的原因应该是wet or dry condition对于研究都不好吧。

PS:我做的时候一直对complacent是什么意思feel confused..

老外提到：
(Govi, choice D is wrong--the rings may be complacent if the two trees。。。

文中有：
these "complacent" rings tell nothing about changes in
climate.

不知道complacent具体神马伊斯，字典上是自鸣得意，=〉自己以为可以得的意思，把树拟人化了？。。反正是贬义的。。