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标题: 请教gwd-21-21 [打印本页]

作者: camilla2006 时间: 2006-7-16 21:15
标题: 请教gwd-21-21

Which of the following most logically completes the passage?

Mastitis is an infection of the udder in cows that, although not dangerous, causes them to give poor-quality milk. Most cases of mastitis are caused by the bacterium Staphylococcus aureus, against which antibiotics are ineffective. However, a related bacterium, Staphylococcus simulans, quickly clears up even severe infections of S. aureus simply by displacing the bacteria. S. simulans is nevertheless unlikely to become the preferred treatment for cases of mastitis, since ______.

certain dangerous bacteria that normally cannot take hold can do so in the presence of S. simulans
the current resistance of S. aureus to antibiotics derives in part from a past pattern of overuse of those antibiotics
the milk from cows infected with S. aureus is generally not of such poor quality as to be entirely unusable
careful farming practice can reduce the incidence of mastitis to a minimum
the only symptom of mild cases of mastitis is the deterioration in the quality of the milk produced

Answer: a

答案A中的take hold究竟是什么意思？A的逻辑推理是什么，没看懂，请牛人帮忙看看。

作者: mbz 时间: 2006-7-16 22:04

take hold = take control

It is saying that Ss can get rid of Sa, but then if you use it, another even more dangerous bacteria will get rid of Ss and take its place to infect cows.

hence, A is right

作者: aborigin 时间: 2006-10-23 22:33

Take hold
Longman: to start to have a definite effect.

If SS is used, the other dangerous bacteria will start to have effect.

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