请教LSAT－4－III－6.12

tony9721 · 发表于 2003-5-18 20:38:00

6. As air-breathing mammals. Whales must once have lived on land and needed hind limbs capable of supporting the mammals' weight. Whales have the bare remnants of a pelvis. If animals have a pelvis, we expect them to have hind limbs. A newly discovered fossilized whale skeleton has very fragile hind limbs that could not have supported the animal's weight on land. This skeleton had a partial pelvis.
If the statement above are true, which one of the following, if also true, would most strongly support the conclusion that the fragile hind limbs are remnants of limbs that land-dwelling whales once had?
(A) Whale bones older than the fossilized hind limbs confirm that ancient whales had full pelvises.
(B) No skeletons of ancient whales with intact hind limbs capable of supporting the mammals' weight have ever been found.
(C) Scientists are uncertain whether the apparently nonfunctioning limbs of other early mammals derived from once-functioning limbs of their ancestors.
(D) Other large-bodied mammals like seals and sea lions maneuver on beaches and rocky coasts without fully functioning hind limbs.
(E) Some smaller sea-dwelling mammals. Such as modern dolphins. Have no visible indications of hind limbs.
正确的答案是A，我想请问一下这里面的逻辑的关系，到底whale的 pelvis，bare remnants of pelvis. Full pelvis. Hind limb, fragile hind limb是如何地进化的，先有的谁后有的谁，答案a的进化的方式我看不懂！
12. The number of North American children who are obese-that is who have more body fat than do 85 percent of North American children their age -is steadily increasing, according to four major studies conducted over the past 15 years.
If the finding reported above is correct, it can be properly concluded that
(A) when four major studies all produce similar results .those studies must be accurate.
(B) North American children have been progressively less physically active over the past 15 years.
(C) The number of North American children who are not obese increased over the past 15 years.
(D) Over the past 15 years ,the number of North American children who are underweight has declined.
(E) The incidence of obesity in North American children tends to increase as the children grow older.
这个数学题，我看了几遍觉得没有一个时正确的答案，，
答案是c，为什么?

albert · 发表于 2003-5-19 11:20:00

6题我也不是特别明白，请牛人指教。
12。胖的小孩占15%这个比例不变，但是人数增加。。说明小孩总人数增加。。所以不胖的小孩（85%）人数也多了。C

cranberry · 发表于 2003-5-19 11:39:00

1，A的意思是比文中的化石要古老的化石说明原来鲸鱼是有完整的骨盆的。说明在陆地生活时，鲸鱼的骨架是足以支撑其后肢进而支撑其身体的，只是后来骨盆才退化了。陆生，完整骨盆，后肢----退化，完整骨盆，后肢退化---退化，部分骨盆...，呵呵，其中加入了偶的注解。

albert · 发表于 2003-5-19 12:10:00

但是好象没起到支持作用吧？
骨盆和limb有什么关系？没提到。。

terry_tin · 发表于 2003-5-19 12:42:00

A起到了支持的作用.这道题所要支持的结论是:the fragile hind limbs are remnants of limbs that land-dwelling whales once had.
原文指出,This skeleton had a partial pelvis,A的发现指出有完整的pelvis,如果较早的骨骼上有完整的pelvis,说明文中发现的骨骼是以前的残留.因此有支持作用

mike1999 · 发表于 2003-5-19 12:51:00

whale必须有 Full pelvis，才能有支撑体重的Hind limb，然后 pelvis退化成patial pelvis, limb变成fragile hind limb。这是的后腿已经不能支撑鲸鱼庞大的体重了。本题为加强题。所以答案重要出现whale有 Full pelvis的论据，选项a恰好是这个意思。
第二题选c没错，就是简单的数学。公式如下：胖子数量=胖子在总人口的比例（15%）*总人口，那么瘦子=瘦子在总人口的比例（85%）*总人口；比例不变，而胖子多了，那么总人口一定也多了，那么瘦子一定也多了

hz · 发表于 2003-5-19 12:56:00

If animals have a pelvis, we expect them to have hind limbs.
更古老的鲸鱼有had full pelvises→更古老的鲸鱼had hind limbs
support the conclusion that the fragile hind limbs are remnants of limbs that land-dwelling whales once had

albert · 发表于 2003-5-19 13:26:00

我主要是觉得这里面的逻辑关系没象其他题那么强.

这道题所要支持的结论是:the fragile hind limbs are remnants of limbs that land-dwelling whales once had.

原文：If animals have a pelvis, we expect them to have hind limbs.
加上A的信息：更古老的鲸鱼有had full pelvises
能一定推出：更古老的鲸鱼had hind limbs吗？也许也能推出更古老的鲸鱼只是有fragile hind limbs
如果是后者，结论就有点奇怪：
the fragile hind limbs are remnants of limbs that land-dwelling whales once had.
因为更古老的鲸鱼只是有fragile hind limbs，当然谈不上remnants...

请教LSAT－4－III－6.12

请教LSAT－4－III－6.12

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