[Helr题库] Helr老师逻辑题，Prep08 按题目类型分类

Lymedisease is caused by a bacterium transmitted to humans by deer ticks.  Generally, deer ticks pick up the bacteriumwhile in the larval stage by feeding on infected white-footed mice.  However, certain other species on which thelarvae feed do not harbor the bacterium. If the population of these other species were increased, more of thelarvae would be feeding on uninfected hosts, so the number of ticks acquiringthe bacterium would likely decline.

Whichof the following would it be most important to ascertain in evaluating theargument?

A.Whether populations of the other species on which deer tick larvae feed arefound only in areas also inhabited by white-footed mice

B.Whether the size of the deer tick population is currently limited by theavailability of animals for the tick's larval stage to feed on

C.Whether the infected deer tick population could be controlled by increasing thenumber of animals that prey on white-footed mice

D.Whether deer ticks that were not infected as larvae can become infected asadults by feeding on deer on which infected deer ticks have fed

E.Whether the other species on which deer tick larvae feed harbor any otherbacteria that ticks transmit to humans

1.     由问题问法得知，此题是评估类的题目。

2.     找到前提和结论：

结论句是：“The number of ticksacquiring the bacterium would likely decline”

3.     判断推理模式：

通过前提和结论的关系，首先可以排除类比，统计枚举，和方案推理。又由前提与结论发生的逻辑时间，我们知道，本题是一个用前提的条件来预测结论的产生。所以前提先发生，而结论后发生。

前提（因）是：“不含有细菌的食物数量增加，大部分幼虫将会吃没有被感染的食物”

结论（果）是：“被感染的幼虫数量将会下降”

4.     找到答案方向：

因果模式推理有两个CQ：

CQ1：因果概括问题。

CQ2：干扰因素问题。

因果类型的题目，答案选项必须说出一个因的导致结论可信度变化的特点或者是直接涉及到因果之间的联系。

选项分析：

A.    鹿的寄生虫所吃的其他物种居住的地方是不是仅在白脚老鼠也居住的地方？该选项是“没有被感染的食物”的居住地的特点，但是该特点并不会影响“被感染的寄生虫数量将会下降”的可信度。（只要数量上去了，无论住在哪里，都会增加被吃的可能性）

B.    Correct. 现在鹿的寄生虫的数量是否受到食物的限制？这个选项涉及到了一个“因”的特殊特点。如果寄生虫现在食物不足的话，那么当食物种类和数量增加的时候，只能活更多的寄生虫，而不会减少吃某种食物的幼虫的数量的下降。

C.    被感染的鹿的寄生虫数量会不会因为捕食白脚老鼠的其他动物的数量上升而减少？该选项提供了另外一个可以导致原文“果”的“因”，即使捕食白老鼠的动物增加，白老鼠数量下降，可能会导致被感染的幼虫数量下降，但不影响原文提供的因果关系。即不涉及原文的因，不能削弱因果推理模式。

D.    成年没有被感染的鹿的寄生虫会不会因为被同被感染的寄生虫喂食一样的东西而感染？这个文段基于感染的幼虫数能否被控制，该选项不涉及“因”和“果”。

鹿幼虫吃的其他种类食物是否含有可以传播给你的细菌？该选项不是“因”所具有的特点，（因仅仅涉及了白脚老鼠），也不涉及因到果之间的联系。

还有另一个版本的题目：

Lyme disease is caused by a bacterium transmitted to humans by deer ticks.Generally deer ticks pick up the bacterium while in the larval stage fromfeeding on infected whitefooted mice. However, certain other species on whichthe larvae feed do not harbor the bacterium. Therefore, if the population ofthese other species were increased, the number
of ticks acquiring the bacterium? and hence the number of people contractingLyme disease-would likely decline.
Which of the following, if true, most strengthens the argument?
A. Ticks do not suffer any adverse consequences from carrying the bacteriumthat causes Lyme disease in humans.
B. There are no known cases of a human's contracting Lyme disease throughcontact with white-footed mice.
C. A deer tick feeds only once while in the larval stage.
D. A single host animal can be the source of bacteria for many tick larvae.
E. None of the other species on which deer tick larvae feed harbor other bacteriathat ticks transmit to humans.

OA is C