gwd-13-32

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Q32:

Macrophages are cells that play a role in the response of the immune system of mice and other mammals to invasive organisms such as bacteria.  Unlike other mice, mice that are genetically incapable of making these particular cells do not show elevated levels of nitrates when infected with bacteria.

The statements above, if true, provide the most support for which of the following conclusions?

I chosed C.

The premise of the sentence have two part:
1.Macrophages play a role in the response invasive organisms such as bacteria.
2.mice without Macrophages do not show elevated levels of nitrates when infected with bacteria
Here we see a gap between "elevated levels of nitrates" and "Macrophages play a role in the response".

C tell us the relationship between "Macrophages's role" and "nitrates", and that build a bridge on the gap, and make this sentence perfect.

However, A is out of scope talking about mice unable either to make macrophages or to make them in sufficient numbers

to be discussed...

答案为C

1。 关键在于理解UNLIKE，Unlike other mice, mice that are genetically incapable of making these particular cells do not show elevated levels of nitrates when infected with bacteria意思为：不能造M的老鼠感染细菌时硝酸盐没有显示升高。能造M的老鼠感染细菌时硝酸盐显示升高（UNLIKE）。C选项说出硝酸盐升高的两种方式，PRODUCTION和 INHIBIT。

2。其它易排除，A较混淆。A的问题在于sufficient。怎样才算sufficient，这概念太含糊，归纳题是不允许这种含糊概念的，再说对那些造M量不足的老鼠，不见得会用其它方式抵抗细菌，难道就不允许由于M细胞不够而生病或根本没事吗。其实我一眼就不喜欢A，它不象归纳题选项，好像跟原文关系不大。感觉上新信息太多，又是some other way，又是sufficient。

我想原文无法得知Injections of nitrates into mice that lack macrophages 是否enhance the ability of these animals’ immune systems to fight off infection.

It's a little out of scope.

请指教!!

I choose B, why is B wrong? thank you

我还是不能理解为什么选C,好像昨天梦里明白了，今天坐在电脑前有不明白了。

原文都说：mice that are genetically incapable of making these particular cells ，即Ｍ，C选项还在说M,C不是无关选项么？原文大概意思：不产M的mice,N不高，C.。还在说M,文章都说不产了