Q19:

Which of the following most logically completes the passage?

A certain tropical island received food donations in the form of powdered milk for distribution to its poorest residents, who were thought to be malnourished. Subsequently, the rate of liver cancers among those islanders increased sharply. The donated milk was probably to blame: recent laboratory research on rats has shown that rats briefly exposed to the substances aflatoxin tend to develop liver cancer when fed casein, a milk protein. This result is relevant because _______.

1. in the tropics, peanuts, a staple of these island residents, support a mold growth that produces aflatoxin
2. the liver is more sensitive to carcinogens, of which aflatoxin may be one, than most other bodily organs
3. casein is not the only protein contained in milk
4. powdered milk is the most appropriate form in which to send milk to a tropical destination
5. the people who were given the donated milk had been screened for their ability to digest milk

Answer:A

我看不出A的PEANUTS和文章有什么联系啊？

This result is relevant because _______.这个是问支持吧？

relevant和evaluating the argument同类. 答案的是和非要对原文起支持和削弱.

原文前提: 1) island residents喝了牛奶 2) island residents肝癌上升 3) Lab rats接触过aflatoxin后又吃了牛奶脂肪, 就得了肝癌.

原文结论: 牛奶造成island residents肝癌上升

不难看出要得到结论, 我们需要知道island上有没有aflatoxin. A说出了这点, 故答案. 有了A, 对结论加强. 没有了A, 对结论削弱.