OG LIFE EXPANTANCY 正确答案不是削弱了前提吗

desperatemonkey · 发表于 2018-9-5 20:25:32

"Life expectancy" is the average age at death of the entire live-born population. In the middle of the nineteenth century, life expectancy in North America was 40 years, whereas now it is nearly 80 years. Thus, in those days, people must have been considered old at an age that we now consider the prime of life.

Which of the following, if true, undermines the argument above?

AIn the middle of the nineteenth century, the population of North America was significantly smaller than it is today.分析该选项
BMost of the gains in life expectancy in the last 150 years have come from reductions in the number of infants who die in their first year of life. 分析该选项
CMany of the people who live to an advanced age today do so only because of medical technology that was unknown in the nineteenth century. 分析该选项
DThe proportion of people who die in their seventies is significantly smaller today than is the proportion of people who die in their eighties. 分析该选项
EMore people in the middle of the nineteenth century engaged regularly in vigorous physical activity than do so today.分析该选项

desperatemonkey · 发表于 2018-9-5 20:26:56

正确答案选B
这道题目前提不是以前寿命40岁，现在寿命80岁
结论是人们对于老年的认知会发生改变曾经的老年现在还认为是黄金年龄
如此正确选项不是削弱了前提吗？？？？

desperatemonkey · 发表于 2018-9-5 20:29:22

再贴一道题讲筑巢是文化差异不是基因差异的
Male bowerbirds construct elaborately decorated nests, or bowers. Basing their judgment on the fact that different local populations of bowerbirds of the same species build bowers that exhibit different building and decorative styles, researchers have concluded that the bowerbirds` building styles are a culturally acquired, rather than a genetically transmitted, trait.

Which of the following, if true, would most strengthen the conclusion drawn by the researchers?
AThere are more common characteristics than there are differences among the bower-building styles of the local bowerbird population that has been studied most extensively. 分析该选项
BYoung male bowerbirds are inept at bowerbuilding and apparently spend years watching their elders before becoming accomplished in the local bower style. 分析该选项
CThe bowers of one species of bowerbird lack the towers and ornamentation characteristic of the bowers of most other species of bowerbird. 分析该选项
DBowerbirds are found only in New Guinea and Australia, where local populations of the birds apparently seldom have contact with one another. 分析该选项
EIt is well known that the song dialects of some songbirds are learned rather than transmitted genetically.

desperatemonkey · 发表于 2018-9-5 20:30:49

这道题不能选A 不是因为A否定了前提里说的不同地方B鸟的巢不一样
有点儿懵求大神指导

kluivert · 发表于 2018-9-6 02:39:57

desperatemonkey 发表于 2018-9-5 20:26
正确答案选B
这道题目前提不是以前寿命40岁，现在寿命80岁
结论是人们对于老年的认知会发生改变曾经的老年 ...

前提：19世纪平均寿命40岁，而现在为80岁
结论：因此，19世纪会被认为old年纪，而现在被认为是黄金年龄

B,过去150年，人的平均寿命增加得益于出生儿死亡率的下降

清楚明了，这说明19世纪平均寿命短是因为幼儿死亡率太高，严重拉低寿命...和绝对年龄没关系。。。完全可能有很多70、80岁的人，结果被deceased infant 拉低平均年龄，所以结论说现在的黄金年龄（应该refer to 30s,40s) 在过去是老人的说法不对

B如何削弱前提了？b只是补充条件，说明前提是如何达到的 ...

个人看法，欢迎指正

kluivert · 发表于 2018-9-6 02:55:17

desperatemonkey 发表于 2018-9-5 20:30
这道题不能选A 不是因为A否定了前提里说的不同地方B鸟的巢不一样
有点儿懵求大神指导 ...

a直接排除啥情况都说明不了

Local bowerbird 建巢的风格相似多于不同。。。能说明啥呢 ...

结论: culturally acquired 而非genetically transmitted

a压根不能证明什么 .. 能说明是后来学的？基因遗传？都不能

B直接说是生来无能，后来看着成年鸟学的

OG LIFE EXPANTANCY 正确答案不是削弱了前提吗

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