相关推荐:
>>>2017年考研现场确认时间及地点汇总
>>>全国各地2017年考研报考点汇总
>>>2017年考研时间、研究生考试时间安排
>>>2017年考研大纲下载及解析汇总
>>>2017年全国硕士研究生招生简章专题
新东方网校推荐:2017年考研政治、英语、数学课程!!点击进入免费试听>>
As if that weren't confusing enough, two new studies published last week in the New England Journal of Medicine investigated the possible effects of mercury on the heart, and they seem to have reached contradictory conclusions. One found no clear link between mercury levels and heart disease; the other found that men with high levels of mercury in their toenails were more likely to suffer a heart attack than those with low levels. What are we to make of this? The first thing to remember is that this is how science proceeds, by fits and starts and seemingly contradictory results that get resolved only by further study. The second is that not all fish are created equal.
Compared with all the other things you might eat, fish are an excellent source of protein. They tend to eat algae as part of their natural life cycle, converting it into omega-3 fatty acids that can improve your cholesterol profile. But it's also true that our waterways have become increasingly contaminated with all sorts of pollutants, including mercury, and that these pollutants tend to accumulate at different levels in different species. The fish most at risk are predators high in the pelagic food chain, such as swordfish and sharks (see chart)。
It was to test the effects of mercury on the heart that the two new studies compared the mercury levels in clippings from toenails, where heavy metals tend to be deposited. In one study, researchers led by Dr. Eliseo Guallar at Johns Hopkins found that European and Israeli men with the highest mercury levels were nearly 2.2 times as likely to have a heart attack as those with the lowest levels. The other study, led by Dr. Walter Willett at the Harvard School of Public Health, looked at a selection of American men and found no connection between mercury exposure and risk of heart disease, although Willett told me a “weak association” cannot be ruled out.
For most of us, eating two servings of fish a week should not pose any problems. Guallar, who hails from coastal Spain, continues to flavor his paella with salmon, which has negligible mercury levels. Willett eats swordfish only about twice a month——because of its expense, not any fear of mercury. Fish-oil supplements are high in omega3 fatty acids and probably don't contain as much mercury as whole fish. But they don't taste nearly as good.
注(1):本文选自Time; 12/9/2002, p99;
注(2):本文习题命题模仿对象2005真题Text 1;
1. In the opening paragraph, the author introduces his topic by
[A]making a comparison
[B]justifying an assumption
[C]posing a contrast
[D]explaining a phenomenon
2. The phrase “by fits and starts”(Line 6, Paragraph 2) most probably means _______.
[A]something happens smoothly
[B]something keeps starting and then stopping again
[C]something deserves a lot of effort
[D]something is troublesome
3. Clippings from toenails were chosen for the research most probably because _______.
[A]they are more likely to contain mercury
[B]they influence a person‘s heart
[C]they can be easily obtained
[D]they are connected with the heart
4. The views of Dr. Eliseo Guallar and Dr. Walter Willett are ______.
[A]identical
[B]similar
[C]opposite
[D]complementary
5. What can we infer from the last paragraph?
[A]Fish is no threat to Man.
[B]Do not be frightened by some fish.
[C]Eat Fish-oil supplements instead of fish.
[D]Taste is more important than the safety of the food.
答案:CBACB
2017考研英语阅读理解考前冲刺试题第十三套.doc