GRE·94-10考题—（4）

Moas were tall, flightless birds that lived only in New Zealand.
Before humans settled in New Zealand, moas had no serious predators and
were plentiful. Moas became extinct after humans began hunting them.
So hunting by humans must have caused the moas extinction.
　
Which of the following, if true, most seriously weakens the argument above?

Some moa species lived in parts of New Zealand that were among the
　last to be settled by humans.
Humans in New Zealand hunted a mammalian species that, though vulnerable
　to indigenous predators, never became extinct.
Humans introduced to New Zealand several animal species that preyed
　on moas.
Moas still existed in some parts of New Zealand approximately 500 years
　after the arrival of the first humans in New Zealand.
Some species of moa were able to outrun humans.

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答案：(C)

问题：下面那一个，if true，最严重削弱上面的论述？
读题：Maos是仅存在于新西兰的一种高大但不会飞的鸟。在人定居新西兰之前，Maos没有
　　　什么可怕的天敌，数量极多。当人们开始猎取它们后，Maos几乎绝迹了。所以，
　　　肯定是人类的打猎造成了Maos的绝迹。
　
分析：上面是一个事实，Maos绝迹；认为人类的打猎是原因。
反对：　1、有其他的原因导致其绝迹
　 2、直接说人类的打猎和Maos绝迹无关。
　
A. 一些Maos栖息在新西兰人类定居最晚的一部分地区。
B. 新西兰人也猎取一种哺乳动物。这种动物虽然也易受本地天敌的攻击，却并未灭绝。
C. 人们引入新西兰好几种捕食Maos的动物。
　　（不是打猎造成的，而是动物捕杀）
　
D. 大约第一批人进驻新西兰500年之后，Maos仍存在于新西兰的某些地区。

　 During six days, Monday through Saturday, a walker is planning to
take five walks—the gorge walk, the lake walk, the pinewoods walk. the
river walk, and the village walk—at a mountain resort. The village
walk requires two entire consecutive days; the other four walks each
require exactly one entire day. The walker s plans will conform to
the following constraints, imposed by the nature of the walks:
　
　The gorge walk must be planned for Monday or else for Tuesday.
　Friday and Saturday cannot be the pair of days for which the village
　　walk is planned.
　The lake walk can be planned for neither t