lsat（section 1）1-8

tongxun

各位G友：
由今天起，我们将在本版面集中讨论LSAT的逻辑，每帖固定8题。
欢迎大家的参与！！！！！[em12][em26]

workhard77

8. Neuroscientists are making progress in discovering more about the cause of Alzheimer's disease. Alzheimer's disease patients suffer from dementia and sever memory loss. Autopsies performed on such patients have revealed the presence of brain lesions caused by abnormal protein deposits. Similar deposits are also found in the brains of elderly patients who do not suffer from Alzheimer's disease. It follows that [U]everyone[/U] who lives long enough will eventually develop Alzheimer's disease.

Which one of the following statements, if true, most seriously undermines the conclusion that everyone who lives long enough will eventually develop Alzheimer’s disease?

(A) The lesions found in the brains of non-Alzheimer's disease patients are far less extensive than those found in the brains of Alzheimer’s disease patients.
(B) The developing brain produces a greater number of cells than it will ever use. The extra cells are later destroyed by what biologists call “programmed cell death.”
(C) The procedure that allows scientists to discover the presence of protein deposits during an autopsy is not yet refined enough to ensure detection of the lesions in all patients.
(D) Autopsies have shown that some people lack the chemical necessary for protein deposits to cause brain lesions.
(E) Though most Alzheimer’s disease patients develop the disease when they are in their late fifties to early seventies, the frequency of patients who develop the disease in their forties is on the rise.
--------------
结论：所有人只要足够老都会得Alzheimer's disease. （我认为关键在everyone）
evidence：验尸说明Alzheimer's disease患者存在由反常蛋白质沉淀物造成的大脑损伤，在非Alzheimer's disease患者的大脑中也存在类似物质。

答案D，切断evidence和结论的关系，说明蛋白质沉淀物需要与chemical necessary共同作用才能造成对大脑的损伤（brain lesions），而some people lack，所以not "everyone"会得Alzheimer's disease

A. 强调了范围"far less extensive"，不能直接削弱
B. 无关
C. 与原论据相悖，在CR中我们必须相信题干所述的真实性
E. "most", "frequency"都只能说明特殊情况

byw:
刚刚这题我也有点迷糊
想来想去只有这么解释了 ，也许有更好的。洗耳恭听：）
ok,该睡觉了的说...
[em19]

[此贴子已经被作者于2002-10-23 0:58:17编辑过]

workhard77

6. No senator spoke at the convention unless he or she was a Democrat. No Democrat both spoke at the convention and was a senator

Which one of the following conclusions can be correctly drawn from the statements above?

(A) N one but senators spoke at the convention.
(B) No Democrat spoke at the convention.
(C) Only Democrats spoke at the convention.
(D) No senator spoke at the convention.
(E) Some Democrat senators spoke at the convention.
-----------------------------
首先说明这好像是lsat中专有的题目，gmat中没见过
答案D
看题干：
第一句
=〉senator=not spoke at the convention+spoke at the convention (only if he Democrat)
=〉senator与Democrat的交集spoke at the convention
第二句
=〉“Democrat+senator+spoke at the convention”三者和一的情况为零

SO, No senator spoke at the convention. （画张文氏图更明了）
-----------------------------

[此贴子已经被作者于2002-10-23 0:54:42编辑过]

workhard77

7. If Sarah were a concert pianist for a major orchestra, she would be famous. She is not a concert pianist since she is not famous.

The conclusion above is unsound because the author does not consider that

(A) Sarah could be a famous actress.

(B) Sarah could be a harpist for a major orchestra.

(C) Sarah could be a pianist with a rock group.

(D) Sarah could be a concert pianist with a minor orchestra.

(E) Sarah could be famous for another reason.
---------------------------
If 1, then 2.=>2是1的必要条件  （这里避免混淆不用一般的A or B or C表示，改用1、2、3 ）
等价于：非2=>非1
这里
1=Sarah were a concert pianist for a major orchestra
2=would be famous
3=be a concert pianist (不等于1)
题干推理过程：
非2=>非3，错误
我认为答案要反对原推理，应指出Sarah still can be a concert pianist （即3可能对）
找"concert pianist"，so D
-----------------------------

workhard77

5. Emperor: The enemy empire across the sea has harassed us for centuries. I want to conquer it and stop it once and for all. What advice can you give me?

Admiral: If you cross the sea, a mighty empire will fall.

Emperor: In that case, prepare the troops. We set sail tonight.

Of the following, the strongest criticism of the Emperor’s decision to invade would be that it

(A) Is certain to lead to the emperor’s defeat
(B) Is based on opinion rather than objective facts about troop strength
(C) Contradicts the Admiral’s statement
(D) Fails to consider fully the possible meanings of the Admiral’s advice
(E) Is a futile strategy for solving the problem at hand
--------------------------------
削弱题
题目不难，我觉得关键是读题后自己先思考一下
答案D：emperor没能完全理解admiral "a mighty empire"的可能含义（the enemy empire across the sea 或 their own country）
-------------------------------

workhard77

我来贴5678，解释得不好还请多多包涵。：）

决战金秋

谢谢可爱的TONGXUN，就是看到你的图片我才加入了这个新家。
最近眼花，没看清你写的标题，不好意思。
那道题我明白了，主要是没看清 Since mercury was commonly ingested in
Beethoven’s time （我看成了我敬爱的Beethoven患了性病）
非常感谢你的分析。我在其他地方再讨教

zyh79

Questions 3-4
The simple facts are these: the number of people killed each year by grizzly bears is about the same as the number of people killed by lightning on golf courses. And the number of people killed by lightning on golf course each year is about the same as the number of people electrocuted by electric blenders. All the horrible myths and gruesome stories aside, therefore, a grizzly bear is in fact about as dangerous as an electric blender or a game of golf.

3. Which one of the following is an assumption that the author relies upon in the passage?

(A) Most incidents involving grizzly bears are fatal.

(B) Grizzly bears are no longer the danger they once were.

(C) The number of fatalities per year is an adequate indication of something’s dangerousness.

(D) A golf course is a particularly dangerous place to be in a thunderstorm.

(E) Something is dangerous only if it results in death in the majority of cases.
--------------------------------------
条件：在bears，golf course和electric blenders上的每年死亡人数相等，
结论：他们同样危险
假设：死亡人数可以充分表明一个东西的危险度。（架桥）

4. Which one of the following, if true, would most effectively undermine the author’s argument?

(A) Although the number of people killed by lightning on golf courses each year is very small, the total number of lightning fatalities is many times greater.

(B) Electric blenders are among the safest household appliances; were the author to compare fatalities from electrical appliances in general, she would get a much higher figure.

(C) Most people would rather take their chances with blenders and golf games than with grizzly bears.

(D) Bears in general—including black, brown, and cinnamon bears, as well as grizzly bears—kill many more people than do electric blenders.

(E) Statistics show that the number of times people use electric blenders each year exceeds the number of times people play golf each year, which in turn far exceeds the number of contacts people have with grizzly bears each year.
-------------------------------------------------
削弱题
E为正确答案，表明死亡数字相等不能反映危险度，比如接触1000次，死一次和接触1次死一次，虽然都是一次，危险性大不相同。
这题告诉我们：比较不能只比较绝对数字，要比较相对数字。
C位迷惑选项，它只说了意愿，但没说明实际情况如何。

tongxun

2、Handwriting analysis—also known as graphology—is a poor way to predict personality types, even though it is used by 3,000 United States firms and by a majority of European companies. In a recent study, five graphologists scored no better than chance in predicting the occupations of forty professionals.

Which one of the following is an assumption necessary to the argument?

(A) People in the same occupation usually do not have the same personality type.

(B) Graphology is an effective means of predicting personality types in non-business contexts.

(C) There are more United States firms that do not use graphology than all the United States and European firms that do use it.

(D) There are several other techniques for predicting personality types that are more accurate than graphology.

(E) There is a correspondence between type of personality and choice of occupation.
---------------------------------
选项A：无关选项。因为不管相不相同，若有效，就能准确地预测出来。
选项B：题干中没有讲到非商业系统的问题。更没有比较问题。
选项C：这种比较也是题干中没有提供的信息。无关选项。
选项D：题目没说其他的方法。因此，也是无关选项。
选项E：由于作者的推论是用“预测职业”来做论据，推出它is a poor way to predict personality types，因此，作者的假设必定是基于两者之间有必然的联系。
正确答案是E。

tongxun

决战金秋：这是我的lsat section 1 的专帖啊。以后不能再来专帖发贴了啊。在这个版面中发新帖。
我认为答案应该是狒狒说的B。
测定水银的目的是确定他有没有患性病。但若水银是大家普遍服用的一样东西，则测出来也不能说他患了性病。因此，在B的时代，至少有一部分人，是不服用水银的，这时才能确定。