[求助]og10 173

rpch2004

答案是A，有好心人帮忙分析一下吗？

173. Researchers have found that when very overweight people, who tend to have relatively low metabolic rates, lose weight primarily through dieting, their metabolisms generally remain unchanged. They will thus burn significantly fewer calories at the new weight than do people whose weight is normally at that level. Such newly thin persons will, therefore, ultimately regain weight until their body size again matches their metabolic rate.

 

The conclusion of the argument above depends on which of the following assumptions?

(A) Relatively few very overweight people who have dieted down to a new weight tend to continue to consume substantially fewer calories than do people whose normal weight is at that level.

(B) The metabolisms of people who are usually not overweight are much more able to vary than the metabolisms of people who have been very overweight.

(C) The amount of calories that a person usually burns in a day is determined more by the amount that is consumed that day than by the current weight of the individual.

(D) Researchers have not yet determined whether the metabolic rates of formerly very overweight individuals can be accelerated by means of chemical agents.
                

(E) Because of the constancy of their metabolic rates, people who are at their usual weight normally have as much difficulty gaining weight as they do losing it.
                

[此贴子已经被作者于2008-5-17 16:27:42编辑过]

rpch2004

牛牛都吃草去了吗？

yinlixiao

C为什么不对？
我对排除无关选项还是掌握不好。
我知道A一定对，但是在考试的时候，如果快捷的排除C呢？
这题结论是长胖，怎么呢推出这个结论呢？如果consume > burn， 就长胖。文中给出了burn 少这个前提，如果答案提供更一个假设，consume一样或者更多，结论就成立了，就会胖。
not+weaken验证

C 指出burn跟consume有关系，但是没有指出它们之间的关系对体重的变化有作用。不能推出结论。

yinlixiao

请牛人指导如何排除C!

yi11

文章：超级大胖子新陈代谢慢，通过节食减肥新陈代谢速度不变。这些人瘦了以后燃烧的脂肪也就比本来瘦人燃烧脂肪少。结论是这些人最后还是得胖回去。
问题问assumption。

burned calories比同样体重人少-->体重增加

(B)(E)说的是不胖的人，直接排除。(D)提到chemical agents无关概念排除。

(C)burned calories更多得受到consumed calories影响而不是受体重影响，但是consumed calories是多还是少没有给出，所以根本看不出来影响的结果是burned calories增加减少还是不变，所以无关。其实还有个更快的方法，文章中"burn significantly less calories"是已知前提，那么正确性不能怀疑，所以burned calories由谁影响根本不影响这个burned less calories少这个已给事实。

(A)说很少有节食减肥以后的大胖子都继续吃的比同样体重的人少。+not是很多减肥以后的大胖子都继续吃得比同样体重人少。大胖子们减肥就是通过吃得少，如果继续吃得少，那么不可能胖回去，这就和结论相反了。所以(A)是assumption。这里要是觉得自己数学好想计算到底增加体重的具体量就比较容易自己把自己搞糊涂了(total cal=burned cal+积累的cal，虽然吃得少，烧得少，但是剩下积累的也少，那到底总体重多了还是少了？晕死了。。。）。