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Mice that have been given morphine are very likely to develop blood poisoning because bacteria that normally reside in the intestine typically respond to morphine by migrating into the bloodstream. However, when mice are given both morphine and the new drug naltrexone, blood poisoning is much less frequent, although it does still occur. These results provide support for researchers’ prediction that naltrexone will turn out to be toxic to certain types of bacteria.

Which of the following, if discovered to be true, would most seriously weaken the support for the researchers’ prediction?

Conditions other than the presence of intestinal bacteria in the bloodstream can cause blood poisoning in mice.

以下是引用kallyli在2006-7-11 18:31:00的发言：
B is the best answer to weaken the support of the researchers' prediction that naltrexone will turn out to be toxic to certain types of bacteria, for the decrease frequent of blood poisoning is not because of the inhibits of bacteria themselves(toxic to them) but of the migration of intestinal bacteria into the bloodstream.
while in E, there is even no mention of naltrexone which is the central idea of the researchers' prediction.

可以解釋成N單獨存在時也不會造成blood poisoning所以不會toxic to certain types of bacteria嗎?

if the blood poisoning is caused by other reason (as described in B), then the researchers’ prediction becomes groundless (weakened).

Choice B gives another way by which the blood poisoning does not happen, ie. if the blood poisoning takes place when the bacteria migrate from intestine into bloodstream, then the new drug functioning by inhibiting the migration into bloodstream rather than poisoning some bacteria - the researchers' prediction.

题目说老鼠服用了吗啡之后，在肠里的一些细菌就会跑到血液中，导致老鼠血液中毒。那些服用了吗啡之后又吃了N的老鼠发生血液中毒的频率却大大降低了。结论是说N会变得对某些种类的细菌有毒害作用。问如何削弱。

B说，N其实是阻止那些肠里的细菌跑去血液里－就是说只是阻止，不是毒害它。正确。

我想我是没有读懂这句话的意思： Naltrexone inhibits morphine from triggering the migration of intestinal bacteria into the bloodstream. 是说N 阻止morphime 通过 triggering ..bacteria into the bloodstream 后面这半句怎么理解啊。是说N通过发起/控制细菌的migration 来阻止morphime 的？一般来讲"trigger" 都是做“发起，启动“ 的意思吧。如果是这样的话这个答案就正好反了

实际上就是toxic和inhibit的细微差别，我们阅读的时候，因为不能精确理解文章意思，通常只记住褒贬，此题就是最大的教训。尤其是逻辑题，上下句之间的细微改变，就直接决定了我们能不能作出assumption\supporting\weakening题型。

以下是引用ly365在2006-7-11 16:30:00的发言：

Q40:

Which of the following, if discovered to be true, would most seriously weaken the support for the researchers’ prediction?

After being administered to mice, naltrexone does not pass from the bloodstream into the intestine.
Naltrexone inhibits morphine from triggering the migration of intestinal bacteria into the bloodstream.
Mice that have been given naltrexone but not morphine have no greater risk of developing blood poisoning than do mice that have not been given either substance.
The increased risk of blood poisoning is not the only harmful effect on mice of being given morphine.

Conditions other than the presence of intestinal bacteria in the bloodstream can cause blood poisoning in mice.

答案B，我选E 请教

我是这样想的，前面说的是，M单独使用，会使bloodstream中毒；

然后是：M和新药一起使用，虽然还会中毒，但是没那么频繁了。

楼上好几位说的是一个意思。查了下，血中毒就是败血症的意思。