LSAT问题请教(lsat-8-ii-19& lsat-8-ii-20)

albert · 发表于 2003-5-8 09:40:00

新来乍到。。。请多多关照
19-20 is based on the following passage:

In a rain cloud, water molecules containing oxygen-18 are rarer than water molecules containing normal oxygen. But in rainfall, a higher proportion of all water molecules containing oxygen-18 than of all water molecules containing ordinary oxygen descends to earth. Consequently, scientists were surprised with the measurements along the entire route of rain cloud’s passage from above the Atlantic ocean, the site of their origin formation, across the Amazon forest, where it rains almost daily, showed that oxygen-18 content of each of the clouds remained fairly constant.
19.    which of the follow statement, if true, best help to resolve the conflict between scientists’ expectation, based on the known behavior of oxygen-18, and the results of their measurements of the rain clouds’ oxygen-IS content?
(b) Like the oceans, tropical rain forests can create or replenish rain clouds in the atmosphere above them
(d) The amount of rain recycled back into the atmosphere from the leaves of forest vegetation is exactly the same as the amount of ram in river runoffs that is not recycled into the atmosphere
为什么是B？

20 which of the following reference about an individual rain cloud is supported by the passage
(a)    Once it is form over the Atlantic, the rain cloud contain more ordinary oxygen than oxygen-18
(c)    The clouds rainfall contains more oxygen-18 than ordinary oxygen
为什么是A，我觉得A 和 C都对。。

另：我用的LSAT电子版本不能拷贝题目，每次想问题目都要手敲一遍。。好麻烦。。请问大家有没有别的版本的LSAT题目，或者有什么别的办法。。
谢谢。。

joywzy · 发表于 2003-5-8 10:24:00

你可以下载新的版本的E-LSAT,这样不用打字,直接复制,贴粘即可.

good luck.

greenfish · 发表于 2003-5-8 10:27:00

以下是引用albert在2003-5-8 9:40:00的发言：
另：我用的LSAT电子版本不能拷贝题目，每次想问题目都要手敲一遍。。好麻烦。。请问大家有没有别的版本的LSAT题目，或者有什么别的办法。。
谢谢。。

先选定区域，点击置顶行Edit里的Copy即可。

albert · 发表于 2003-5-9 01:54:00

thank everybody..
btw, jobzxy, where to download the new version of lsat? I only see old version lsat.

Is there anybody can answer my lsat question??

help!!!!

mindfree · 发表于 2003-5-9 02:01:00

1. 我认为B的关键在于like ocean, 说明rain forest在功能上和ocean有相似性,这样就能够解释oxygen-18的含量恒定的现象.

D只是在量上给出了解释, 没有对质进行解释, 对oxygen-18的含量不能解释.

2. C是错的, 原文说rain cloud中含oxygen-18的水分子要远少与含普通氧的水分子, 说明oxygen-18要少于ordinary oxygen.

albert · 发表于 2003-5-9 02:31:00

但原文是 " But in rainfall, a higher proportion of all water molecules containing oxygen-18 than of all water molecules containing ordinary oxygen descends to earth."
指是rainfall oxygen-18含量高。。。不是正好和Ｃ吻合吗？

mindfree · 发表于 2003-5-9 03:21:00

这句话的意思是在降雨中中含oxygen-18水分子要多于含ordinary oxygen的水分子. 既虽然在rain cloud中总体的oxygen-18水分子少于ordinary oxygen水分子, 形成降雨时雨水中的oxygen-18的水分子要多于ordinary oxygen的水分子.

albert · 发表于 2003-5-9 10:02:00

对啊。。所以20中（c)不是应该也对吗？
(c) The clouds rainfall contains more oxygen-18 than ordinary oxygen

wubin · 发表于 2003-5-10 09:31:00

albet 正如mindfree曾经所说逻辑阅读和阅读理解不同，每句话都很重要（一般情况下是这样）一定要仔细阅读理解，我刚看到你的问题时也是一愣，但仔细看这句话——a higher proportion of all water molecules containing oxygen-18 than of all water molecules containing ordinary oxygen descends to earth——我们会发现他翻了费费所说的比较对象错误，句中说是含氧18的所有水分子的一个比例和含通常氧原子的所有水分子的一个比例相比前一个比例大，但并不能推出The clouds rainfall contains more oxygen-18 than ordinary oxygen ，因为可能The clouds rainfall contains less oxygen-18 than ordinary oxygen，但
含oxygen-18 的水分子中大部分将落到了地面。不知你理解了吗？举个数学例子：10个水分子（相当于all water molecules containing oxygen-18 ），100个水分子（相当于all water molecules containing ordinary oxygen ）100〉10，即rainfall中The clouds rainfall contains less oxygen-18 than ordinary oxygen，但最终10个水分子全降落到earth为100%，而100个水分子中只有20各水分子降落到了earth为20%，100%〉20%，好了我只能讲到这里了；

jacy · 发表于 2003-5-10 11:53:00

agree wubin.
The clouds rainfall 不等于the raifall.我想你是看错了.
另外,19题我是这样理解的:既然 across the Amazon forest,oxygen-18 content of each of the clouds remained fairly constant.而在above the Atlantic ocean,water molecules containing oxygen-18 are rarer than water molecules containing normal oxygen.
等于在形成云的时候少,下雨的时候又一样了.因此在运行的过程中,一定有氧18的补充.
正如B所说.揭示了矛盾.

不知道这样理解对不对.

LSAT问题请教(lsat-8-ii-19& lsat-8-ii-20)

LSAT问题请教(lsat-8-ii-19& lsat-8-ii-20)

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