[讨论]OG-175 (大全-9-20）答 tndol

20.   arasitic wasps lay their eggs directly into the eggs of various host insects in exactly the right numbers for any suitable size of host egg. If they laid too many eggs in a host egg, the developing wasp larvae would compete with each other to the death for nutrients and space. If too few eggs were laid, portions of the host egg would decay, killing the wasp larvae.

Which of the following conclusions can properly be drawn from the information above?

(A) The size of the smallest host egg that a wasp could theoretically parasitize can be determined from the wasp’s egg-laying behavior.

(B) Host insects lack any effective defenses against the form of predation practiced by parasitic wasps.

(C) Parasitic wasps learn from experience how many eggs to lay into the eggs of different host species.

(D) Failure to lay enough eggs would lead to the death of the developing wasp larvae more quickly than would laying too many eggs.（A）

(E) Parasitic wasps use visual clues to calculate the size of a host egg.

你问的是这个题吗？哪里不明白？

BCDE的结论都不能从题目中推导出来。B,host 能不能有效抵御没说到，看样子它们只能被动接受，但是只是猜测；C，Parasitic wasps怎么知道下多少蛋也没有说到，只是说它们知道大的下多点 小的下少点，而且多少正好；D，下多下少都对寄生的小wasps不好，但是哪个更不好，并不知道，虽然我们知道不好的原因有区别；E，Parasitic wasps用什么估算下蛋的多少题目中并没有说，我们可能根据常识猜测是看看就知道了，但是这个常识不是题目中给出的，不算数。               A，既然Parasitic wasps知道大蛋多下，小蛋少下，那就是说它们对host egg的大小是有精确把握的（不管为什么），也就是说肯定对大蛋和小蛋的size都有把握，那当然就对小蛋能小到什么程度(只下一个蛋在host egg的时候）有把握了。

vinvent0330:个人意见:原文讲到黄蜂生太多也不行, 生太少也不行------> 只能生刚刚好----->所以我们知道当黄蜂生产一个蛋------>一定是最小的(注意文中的数量差异, 原文讲到总体, 选项讲到个体)

对，OG解释里说的更直接和准确些，就是能确定能被寄生的host egg的最小值（也就是寄生一个wasp蛋），所以是smallest。{Comparing two host eggs in which parasitic wasps have laid different numbers of eggs, it is theoretically possible laid different numbers of eggs, it is theoretically possible to determine what size of host egg would be required for a single wasp egg. This would be the smallest egg the wasp could parasitized, so A is the best answer.}

文章最后一句何意？If too few eggs were laid, portions of the host egg would decay, killing the wasp larvae.

文章是说黄蜂蛋不能多也不能少，即只是说了黄蜂蛋在一个寄主蛋中的数量一定，但没说一个黄蜂蛋最小多大呀，那怎么能判断出寄主蛋最小多大?

默认wasp的egg是大小均匀的，这是衡量host egg大小的尺子。不需要想一个wasp egg多大多小。只能下一个wasp egg的host egg就是最小尺寸的host egg.

思谦说得没错。（其中wasp的蛋是大小一样的隐含假设是根本无须虑及的，你想到这个说明你的思路和ETS还不一样，当然你也不是唯一一个想到这个问题的）

tndol：觉得干扰你的还是跟题目中逻辑没关系的因素，即WASP经常把蛋下到人家的蛋里，下得多了它自然有经验呀！常情嘛！这个常识和题干中逻辑推导过程没有关系。所以理解题目逻辑过程不要联系自己生活常识，甚至自己知道的专业知识。从这个角度来说，如果是你一点都不了解的话题，这个干扰因素就不会干扰你。这样的题在我准备逻辑的时候有大约5道吧，主要是经济类题目等。比如闯红灯和罚款的那个，我自己开车多，总是难以割断自己开车的经验，所以理解起来总是生活常识等与题目逻辑没直接关系的因素干扰对逻辑过程的正确理解。

还有对can be determined 中determine 的理解也是干扰了好几个人的一个因素，讨论这个题目的大约是10个帖子。determine是（从已知条件可以合逻辑地）推导出来的意思。有一个朋友问：host的蛋怎么能由wasp来决定大小呢？就是源于对这个词汇在这个环境下的意思的理解偏差的干扰。

Andrea625，题目中的in exactly the right numbers，就是下面加下划线的部分，是否就是我前面所说：暗含的一只黄蜂蛋下的蛋一样大？

Parasitic wasps lay their eggs directly into the eggs of various host insects in exactly the right numbers for any suitable size of host egg. If they laid too many eggs in a host egg, the developing wasp larvae would compete with each other to the death for nutrients and space. If too few eggs were laid, portions of the host egg would decay, killing the wasp larvae.

呵呵，这个问题还真没有想过。不过按照OG的推理，应该是这样的。思谦同学真是认真啊！

我觉得不必想这个问题，wasp的egg大小问题没有在这道题的逻辑过程中。