阅读题求解答

rebeccahanyyUID: 3249400

Warm-blooded animals have elaborate physiological controls to maintain constant body temperature (in humans, 37℃). Why then during sickness should temperature rise, apparently increasing stress on the infected organism? It has long been known that the level of serum iron in animals falls during infection. Garibaldi first suggested a relationship between fever and iron. He found that microbial synthesis of siderophores-substances that bind iron-in bacteria of the genus Salmonella declined at environmental temperatures above 37℃ and stopped at 40.3℃. Thus, fever would make it more difficult for an infecting bacterium to acquire iron and thus to multiply. Cold-blooded animals were used to test this hypothesis because their body temperature can be controlled in the laboratory. Kluger reported that of iguanas infected with the potentially lethal bacterium A. hydrophilia, more survived at temperatures of 42℃ than at 37℃, even though healthy animals prefer the lower temperature. When animals at 42℃ were injected with an iron solution, however, mortality rates increased significantly. Research to determine whether similar phenomena occur in warm-blooded animals is sorely needed.

4.  If it were to be determined that similar phenomena occur in warm-blooded animals  (lines 14), which of the following, assuming each is possible, is likely to be the most effective treatment for warm-blooded animals with bacterial infections?
(A) Administering a medication that lowers the animals' body temperature
(B) Injecting the animals with an iron solution
(C) Administering a medication that makes serum iron unavailable to bacteria
(D) Providing the animals with reduced-iron diets
(E) Keeping the animals in an environment with temperatures higher than 37℃
答案怎么会选C呢？？

andy600108UID: 2596426

由文中对变温动物的实验可知温度的高低与机体对iron的吸收有关。那么，C选项就比较好理解了吧？

rebeccahanyyUID: 3249400

andy600108 发表于 2012-8-2 16:02
由文中对变温动物的实验可知温度的高低与机体对iron的吸收有关。那么，C选项就比较好理解了吧？

B呢？不是很直接可以推出来么？

samanthalycUID: 2968067

He found that microbial synthesis of siderophores-substances that bind iron-in bacteria of the genus Salmonella declined at environmental temperatures above 37℃ and stopped at 40.3℃. Thus, fever would make it more difficult for an infecting bacterium to acquire iron and thus to multiply. Cold-blooded animals were used to test this hypothesis because their body temperature can be controlled in the laboratory.
这么解释吧：问warm-blooded 就把cold的取反，而这种理科文章要特别注意因果关系，看到thus吧，前面句就是原因，把关键词bind 取反就是unavailable啦！

samanthalycUID: 2968067

鄙人疏见：咱们做题无论是填空还是阅读，不在于理解文意，重在逻辑，而这些逻辑连接词就像数学符号一样，熟悉就对了！

rebeccahanyyUID: 3249400

samanthalyc 发表于 2012-8-2 18:47
鄙人疏见：咱们做题无论是填空还是阅读，不在于理解文意，重在逻辑，而这些逻辑连接词就像数学符号一样，熟 ...

我不理解cold blood和warm blood之间为什么要取反，我觉得应该取同的，因为实验使用cold blood是因为可以随意控制体温，模拟在warm blood动物的情形。。。

い无与伦比ぉUID: 3381372

我觉得答案应该在这句“When animals at 42℃ were injected with an iron solution, however, mortality rates increased significantly.” 前面拿cold-blooded animals做实验的确是为了模拟恒温动物，实验结果是被病毒感染的iguanas在42℃下存活率更高，这只是表面现象，而"When animals..."这句才是问题的根源所在，相当于一个对比实验，注射iron solution后，死亡率就剧增，说明温度影响的是病毒细胞对iron的吸收，也就是说”fever防御“的根源是减少病毒细胞对iron的吸收，同理，要想治疗病毒感染，就要模拟”fever防御“的机制，想办法减少病毒细胞对iron的吸收。A答案并没有错，只是C更合适，因为它从根源上解决问题（A答案的间接目的不就是C的直接目的吗？），注意题干说的也是选”the most effective treatment“，所以选C。（我做这道题的时候选的也是A。。）

Sheldon_CooperUID: 3386930

A选项：降低体温，和原题相反。原题提出体温恒定动物升温是为了抑制细菌。降温的话反而促进细菌

B选项：LZ可能没理解那个mortality 的指代，说的是iguanas,而不是细菌，因为前面句子主语是“When     animals.....”中的animals 而不是细菌，所以增加铁溶液只会加重情况，错

C选项，文中前面提出了 恒温动物升温是为了阻止细菌吸收铁。因此阻止其的方式就是1、升温
                                                                                                                   2、阻止细菌吸收铁，而C选项正是其中一种，所以C正确

D选项，减少含铁的菜确实可以降低细菌，但是针对文中的两个阻止方式而言，没有C说的直接，因此不选

E选项提出的是给动物提供一个高于37度的环境，而并非改变动物体温。这样说，题目提出的是恒温动物，而非冷血动物，这也就说明了其温度不会随着外部变化而改变（常识/文章第一句话的解释得出）因此改变温度不能作用于两个影响细菌的因素，因此错误。

onewakeupUID: 3501016

Sheldon_Cooper 发表于 2013-8-26 23:28
A选项：降低体温，和原题相反。原题提出体温恒定动物升温是为了抑制细菌。降温的话反而促进细菌

B选项： ...

好吧，我选了e，没注意到常识：环境温度不影响warm-blooded动物，要是冷血动物就对了。