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题库 / Prep2012-CR-34
In polluted environments, dolphins gradually accumulate toxins in their body fat, and the larger the dolphin the more accumulated toxins it can tolerate. Nearly 80 percent of the toxins a female dolphin has accumulated pass into the fat-rich milk her nursing calf ingests. Therefore, the unusually high mortality rate among dolphin calves in the industrially contaminated waters along Florida's Gulf Coast is probably the result of their being poisoned by their mother's milk.
Which of the following, if true, most strengthens the argument?
The survival rate of firstborn dolphin calves in the area along Florida's Gulf Coast is highest for those whose mothers were killed before they were weaned.
The rate at which adult dolphins living in the waters along Florida's Gulf Coast accumulate toxins is no higher than that of adult dolphins in comparably polluted waters elsewhere.
Among dolphin calves born in the area along Florida's Gulf Coast, the mortality rate is highest among those with living siblings.
As dolphins age, they accumulate toxins from the environment more slowly than when they were young.
Dolphins, other marine mammals, have a higher proportion of body fat than do most land mammals.
环境污染→ 海豚妈妈的母乳有毒 →小海豚dolphin calves死亡率高
增强？
选项A（√）
The 【survival rate存活率】 of 【firstborn dolphin calves小海豚】 in the area along Florida's Gulf Coast is 【highest 最高】for those whose 【mothers were killed before they were weaned 海豚妈妈在断奶前被杀】.
在佛罗里达州墨西哥湾沿岸地区，那些海豚妈妈在断奶前被杀的海豚幼崽的存活率最高。
= 海豚妈妈死了→ 小海豚还没喝够海豚妈妈的毒奶 → 小海豚体内累积的毒素不够多→ 小海豚还没达到死的标准（所以存活下来）
A 在Florida新出生的海豚存活最高的情况是母亲在他们断奶前就被杀了
B 成年海豚身体的毒素在Florida的和其他地方的没差，这个不是support
C：已知
D：讲到了环境对毒素的影响，与母乳传递的无关
E: body fat与母乳传递无关！
果因:小海豚死得多是因为被妈妈的牛奶毒了。
说明二者之间有因果关系。
calf calve contaminate
dolphin在体内积累的毒素会通过哺乳的方式传递给幼崽，因此在某地非常高的幼崽死亡率可能是因为喝了有毒素的母乳。问support
choice a, 同一片区域内，幼崽成活率最高的群体是那些在哺乳之前母海豚就已经死亡的。correct
Therefore, the unusually high mortality rate among dolphin calves in the industrially contaminated waters along Florida's Gulf Coast is probably the result of their being poisoned by their mother's milk.
注意关注结论：结论是母乳导致了calf的高死亡率，强调的是母乳的作用，而不是高污染的环境对于高死亡率的作用。
读懂A选项！
词汇问题。。
wean 不知道是断奶的意思··· 就选了D，以为年龄和断奶有关系···
做CR的时候一定要时刻关注着题目的总argument 时不时回头看看
这个题虽然做对了！但是险些就掉在坑里了！！
Therefore, the unusually high mortality rate among dolphin calves in the industrially contaminated waters along Florida's Gulf Coast is probably the result of their being poisoned by their mother's milk.
注意关注结论：结论是母乳导致了calf的高死亡率，强调的是母乳的助攻作用，而不是高污染的环境对于高死亡率的助攻作用（很有误导性）
错选C，sibling--兄弟姐妹，C选项说在这个污染的地方，有兄弟姐妹的幼崽在所有幼崽中死亡率越高。这其实说明了并不是奶水造成死亡，反而是因为有兄弟姐妹造成死亡，所以是削弱。
而A选项，意思是，那些在断奶前丧母的幼崽存活率高。断奶前丧母，这表明了他们都没怎么喝奶，或者说喝奶时间比较短，所以存活率高，也就加强了喝污染奶导致死亡。
C 恰好是削弱噢~~~
A -断奶以前妈妈就killed的那些海豚幼崽存活率高，因为喝的少了, 喝进去的toxin也少了。
一词不懂此题就废，Wean断奶
相关因果