请教解释

mjiehu · 发表于 2003-11-10 05:52:00

Because dinosaurs were reptiles, scientists once assumed that, like all reptiles alive today, dinosaurs were cold-blooded. The recent discovery of dinosaur fossils in the northern arctic, however, has led a number of researchers to conclude that at least some dinosaurs might have been warm-blooded. These researchers point out that only warm-blooded animals could have withstood the frigid temperatures that are characteristic of arctic winters, whereas cold-blooded animals would have frozen to death in the extreme cold.
Which one of the following, if true, weakens the researchers’ argument?
(A) Today’s reptiles are generally confined to regions of temperate or even tropical climates.
(B) The fossils show the arctic dinosaurs to have been substantially smaller than other known species of dinosaurs.
(C) The arctic dinosaur fossils were found alongside fossils of plants known for their ability to withstand extremely cold temperatures.
(D) The number of fossils found together indicates herds of dinosaurs so large that they would need to migrate to find a continual food supply.
(E) Experts on prehistoric climatic conditions believe that winter temperatures in the prehistoric northern arctic were not significantly different from what they are today.

天山 · 发表于 2003-11-10 08:42:00

conclusion: at least some dinosaurs might have been warm-blooded
evidence: only warm-blooded animals could have withstood the frigid temperatures that are characteristic of arctic winters, whereas cold-blooded animals would have frozen to death in the extreme cold.
那么这个推理过程中隐藏着assumption: fossils in arctic suggest that dinosaurs there can survive cold winters.
weaken :他因法，断桥法
（D)选项表明：恐龙数量太多，以致于部分恐龙必须迁徙到其他地方觅食。
那么在arctic的化石有可能就是迁徙来的恐龙，他们客死异乡,并未生存下来。这不就断了assumption了吗？
所以（d)正确。

mjiehu · 发表于 2003-11-10 09:22:00

joywzy · 发表于 2003-11-10 10:39:00

以下是引用天山在2003-11-10 8:42:00的发言：
conclusion: at least some dinosaurs might have been warm-blooded
evidence: only warm-blooded animals could have withstood the frigid temperatures that are characteristic of arctic winters, whereas cold-blooded animals would have frozen to death in the extreme cold.
那么这个推理过程中隐藏着assumption: fossils in arctic suggest that dinosaurs there can survive cold winters.
weaken :他因法，断桥法
（D)选项表明：恐龙数量太多，以致于部分恐龙必须迁徙到其他地方觅食。
那么在arctic的化石有可能就是迁徙来的恐龙，他们客死异乡,并未生存下来。这不就断了assumption了吗？
所以（d)正确。

天山,这种的断桥法,好象非要想想,有时会想不出来,这也是断桥???

天山 · 发表于 2003-11-10 11:31:00

weaken 类的难题，这是一个代表。
LSAT与GMAT的逻辑题目有一点点区别，往往就是LSAT的choice项意思有时候并不明显，看起来似乎是无关选项，它需要你根据commonsense，弄清内在含义，有时侯甚至需要inference。也许我们在中国生活，不习惯西方的思维习惯， ETS非常擅用这一招，j经常使我们与correct choice失之交臂。
例如：In 1992, a major newspaper circulated throughout North American paid its reporters an average salary paid by its principle competitors to their reporters. An executive of the newspaper argued that this practice was justified, since any shortfall that might exist in the reporters' salaries is fully compensated by the valuable training they receive through their assignments.
Which one of the following, if true about the newspaper in 1992, most seriously undermines the justification offered by the executive?
A.Senior reporters at the newspaper earned as much as reporters of similar stature who worked for the mewspaper's principle competitors.
B.Most of the newspaper's reporters had worked there for more than ten years.
C.The circulation of the newspaper had recently reached a plateau, after it had increased steadily throughout the 1980s.
D.The union that represented reporters at the newspaper was different from the union that represented reporters at the newspaper's competitors.
E.The newspaper was widely read throughout continental Europe and Great Britain as well as North America.
这道题目我刚开始做的时侯死活都找不出正确答案。后来才知道（B)中，工作超过10年就等于不需要valuable training,才勉强同意（B)为正确答案。
所以LSAT可以练习练习，但考前最好还是回到GMAT的逻辑上来，毕竟LSAT的"reasonable inference"在GMAT中并不多见。

joywzy · 发表于 2003-11-10 11:43:00

天山,我非常赞成你的观点.

在做削弱时,我经常会觉得所有的选项都是无关的,一些可能是自己的思维缺陷,体会不出A与B的关联来.你知道这种情况下,有什么办法吗?

谢谢.

天山 · 发表于 2003-11-10 12:30:00

那要通过具体题目才能讲清楚，你举些例子吧。

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