请教LSAT-2-2-17,LSAT-2-2-18,LSAT-2-2-24

joywzy · 发表于 2003-5-6 19:43:00

1The advanced technology of ski boots and bindings has brought a dramatic drop in the incidence of injuries that occur on the slopes of ski resorts: from 9 injuries per 1,000 skiers in 1950 to 3 in 1980. As a result, the remainder of ski-related injuries, which includes all injuries occurring on the premises of a ski resort but not on the slopes, rose from 10 percent of all ski-related injuries in 1950 to 25 percent in 1980. The incidence of these injuries, including accidents such as falling down steps, increases with the amount of alcohol consumed per skier.

17. Which one of the following conflicts with information in the passage?

(A) The number of ski injuries that occurred on the slopes was greater in 1980 than in 1950.

(B) A skier was less likely to be injured on the slopes in 1950 than in 1980.

(C) The reporting of ski injuries became more accurate between 1950 and 1980.

(D) The total number of skiers dropped between 1950 and 1980.

(E) Some ski-related injuries occurred in 1980 to people who were not skiing.

答案：B，我觉得A，B均可啊？为什么A不行呢？

18. Learning how to build a nest plays an important part in the breeding success of birds. For example, Dr. Snow has recorded the success of a number of blackbirds in several successive years. He finds that birds nesting for the first time are less successful in breeding than are older birds, and also less successful than they themselves are a year later. This cannot be a mere matter of size and strength, since blackbirds, like the great majority of birds, are fully grown when they leave the nest. it is difficult to avoid the conclusion that they benefit by their nesting experience.

Which one of the following, if true, would most weaken the argument?

(A) Blackbirds build better nests than other birds.

(B) The capacity of blackbirds to lay viable eggs increases with each successive trial during the first few years of reproduction.

(C) The breeding success of birds nesting for the second time is greater than that of birds nesting for the first time.

(D) Smaller and weaker blackbirds breed just as successfully as bigger and stronger blackbirds.

(E) Up to 25 percent of all birds are killed by predators before they start to nest.

答案：B，B为什么是削弱呢？

24. There is little point in looking to artists for insights into political issues. Most of them hold political views that are less insightful than those of any reasonably well-educated person who is not an artist. Indeed, when taken as a whole, the statements made by artists, including those considered to be great, indicate that artistic talent and political insight are rarely found together.

Which one of the following can be inferred from the passage?

(A) There are no artists who have insights into political issues.

(B) A thorough education in art makers a person reasonably well educated.

(C) Every reasonably well-educated person who s not an artist has more insight into political issues than any artist.

(D) Politicians rarely have any artistic talent.

(E) Some artists are no less politically insightful than some reasonably well-educated persons who are not artists.

答案：E，其它选项可排除。

可是E与原文讲的矛盾啊？
原文讲的是：most artists are less politically insightful than some reasonably well-educated persons who are not artists.

谢谢。

1stzhang · 发表于 2003-5-6 21:11:00

1、A不对，原文说的是百分比，有可能人数会变，那么两个一乘就不好说了。

2、的确不知道如何削弱的，但是用求同求异知道（B）是求异；（C）是求同,请mindfree来解释

3、请注意原文的用词Most of them ，而答案是some其实可以理解为at least one

joywzy · 发表于 2003-5-7 20:12:00

这是怎么回事呢？!

mindfree · 发表于 2003-5-7 20:32:00

1. 同意1stzhang的意见. 在牵涉到数字和比较的题目中, 要注意的一个问题是:比较的是绝对的数字(absolute value)还是比率(rate, percentage).

2. 我以前回复过此题, CD不支持全文搜索实在是...唉...
B削弱在于它指出是其它原因造成了文中的现象. 这道题也是很典型的:A和B同时发生,于是结论为A-->B. 这类题一般问assumption, 答案可能是:1. 不是B-->A 2. 不是其它原因造成B. 这里的削弱就是第二种情况, 否定了assumption:是其它原因造成的, 原结论就不成立了.

XX通过观察认为孵蛋的成功率和筑巢有关(A,B同时发生==>A-->B). 答案B指出蛋的质量是原因.

3. 是LSAT中常见的题型. Most of people at CD are now studying GMAT ==> Some of those people at CD are not studying. 所以说逻辑题目中的每个字都很重要,尤其是这种表程度,范围,态度的词.

joywzy · 发表于 2003-5-7 22:22:00

明白了，谢谢mindfree and 1stzhang!!!

victorliao · 发表于 2004-9-28 09:35:00

消息标题：再问LSAT2-2-24 insight into political issues

Dear Mindfree:
你可真是个大牛!佩服!也很感谢你回复了那么多贴子.关于你对下题的回复,我有个疑问想请教.http://forum.chasedream.com/dispbbs.asp?boardID=24&ID=3576&page=57
其推理为:most of artists(A)-->less insightful into political issue(B)
E的推理为:some artists(negative A)-->not less insightful ..(negative B).
E为否命题,怎么能推的出呢?
谢谢!我会把你的回答贴上去.

MINDFREE的回答：

First of all, understanding should go before applying any logic concept. In this question, there is no need to use logic as I have explained. Most of us are good --> some of us are not.
Secondly, your reason is not correct. Most A are B = Some A are not B. In this question, negative A will read like "not most artists are less political", which equals "most artists are political".

victorliao · 发表于 2004-9-28 09:37:00

消息标题：RW: 再问LSAT2-2-24 insight into political issues

Dear Mindfree:

I do much appreciate for your kind explanation.Actually what I doubt is that " Most A are B = Some A are not B". May I give an instance for the reasoning:
A: refer to a group of students who score higher than 80 in a math test
B:refers to students who score higher than 60 in the math test
Thus: " Most A are B = Some A are not B" is not acceptable,because some A are still B( A can be a subset of B). Where I am wrong? Pls pay your efforts to point it out.

Mindfree的回答：

You are wrong in that "most A = B" in your example is false. In critical reasoning, it should be "all A = B". If in a math question and you are told most of the numbers in group A are also in group B, then some of those in A is not. If you think otherwise, you will make mistake.

绿岛之旅 · 发表于 2004-11-17 06:06:00

可不可以讲讲 24题中d为什么不多呢？

原文：artistic talent and political insight are rarely found together

选项D：Politicians rarely have any artistic talent

是不是：Politicians和political insight 不对等？

请帮忙指点谢谢

amywangwei · 发表于 2008-6-5 12:18:00

以下是引用绿岛之旅在2004-11-17 6:06:00的发言：

可不可以讲讲 24题中d为什么不多呢？

原文：artistic talent and political insight are rarely found together

选项D：Politicians rarely have any artistic talent

是不是：Politicians和political insight 不对等？

请帮忙指点谢谢

同问，我也在d,e之间犹豫了好半天，最后还是选了d，因为觉得它是结论的转述。为什么不对呢？

请教LSAT-2-2-17,LSAT-2-2-18,LSAT-2-2-24

请教LSAT-2-2-17,LSAT-2-2-18,LSAT-2-2-24

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