GWD T 23 10

yeah529

Macrophages are cellsthat play a role in the response of the immune system of mice and other mammalsto invasive organisms such as bacteria. Unlike other mice, mice that are genetically incapable of making theseparticular cells do not show elevated levels of nitrates when infected withbacteria.
The statements above, iftrue, provide the most support for which of the following conclusions?
A.     Mice that are unable either to make macrophages or to makethem in sufficient numbers will protect themselves from bacterial infections insome other way.
B.     Mice that show elevated levels of nitrates can easily fightoff most types of bacterial infections.
C.     ！In mice, macrophages play a role in the production ofnitrates or inhibit a process by which nitrates are broken down or otherwiseeliminated.
D.     When a healthy mouse becomes infected with an invasiveorganism, the number of macrophages in the mouse’s body decreases.
E.      Injections of nitrates into mice that lack macrophages willnot enhance the ability of these animals’ immune systems to fight offinfection.


答案选C，可是我选了B。我的推理是，mice that are genetically incapable of making these particular cells do not show elevated levels of nitrates when infected with bacteria.的逆否命题就是有提高nitrates，老鼠就有能力产生Macrophages，然后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.  所以提高了nitrates就能够抵抗病毒入侵。这样不对么？？？

sdcar2010

所以提高了nitrates就能够抵抗病毒入侵

This is a stretch. Nowhere in the passage says that macrophage "can easily fightoff most types of bacterial infections." So B is wrong.

yeah529

所以提高了nitrates就能够抵抗病毒入侵

This is a stretch. Nowhere in the passage says that macrophage "can easily fightoff most types of bacterial infections." So B is wrong.

-- by 会员 sdcar2010 (2011/11/26 10:49:15)

这样。。。可是有时候很难搞懂哪一个是stretch。。比如C选项里面说inhibit a process by which nitrates are broken down or otherwise eliminated. 我就觉得是无关选项了-  -牛牛快帮忙一下。我经常结论题这样的推断不出来T^T

sdcar2010

"play a role" is a much softer modifier which could enhance or inhibit.

Granted, GWD questions are not authentic GMAT question. So some not well-crafted questions like this are common.

yeah529

"play a role" is a much softer modifier which could enhance or inhibit.

Granted, GWD questions are not authentic GMAT question. So some not well-crafted questions like this are common.

-- by 会员 sdcar2010 (2011/11/26 12:23:51)

谢谢。。明白了，选个相对正确的才是硬道理！！