gwd5 b为啥不对啊？急！

whygodnotear

Healthy lungs produce a natural antibiotic that protects them from infection by routinely killing harmful bacteria on airway surfaces.  eople with cystic fibrosis, however, are unable to fight off such bacteria, even though their lungs produce normal amounts of the antibiotic.  The fluid on a0.irway surfaces in the lungs of people with cystic fibrosis has an abnormally high salt concentration; accordingly, scientists hypothesize that the high salt concentration is what makes the antibiotic ineffective.

Which of the following, if true, most strongly supports the scientists’ hypothesis?

When the salt concentration of the fluid on the airway surfaces of healthy people is raised artificially, the salt concentration soon returns to normal.

A sample of the antibiotic was capable of killing bacteria in an environment with an unusually low concentration of salt.

When lung tissue from people with cystic fibrosis is maintained in a solution with a normal salt concentration, the tissue can resist bacteria.

Many lung infections can be treated by applying synthetic antibiotics to the airway surfaces.

High salt concentrations have an antibiotic effect in many circumstances.

答案选c,但我不知道b为啥错。各位帮忙看看，多谢   

ethyl

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lismiles

scientists hypothesize that the high salt concentration is what makes the antibiotic ineffective.高盐含量导致抗生素失效。

b. A sample of the antibiotic was capable of killing bacteria in an environment with an unusually low concentration of salt.抗生素的样本能够在低盐含量的环境下杀死细菌。

按照b说的抗生素可能在高盐的环境下也能杀死细菌，削弱结论。

B应该与科学家的结论无关

whygodnotear

他不是说unusually low concentration吗？in a solution with a normal salt concentration, the tissue can resist bacteria. 不是更削弱了么？

lismiles

   When lung tissue from people with cystic fibrosis is maintained in a solution with a normal salt concentration, the tissue can resist bacteria.

“有肺病人的肺部组织在正常盐度的液体中，抗生素就不会失效，肺部组织能够抵抗细菌”支持了科学家说的结论。

whygodnotear

好象有点明白了