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  3. When Lewis Ziska wanted to see how a warmer wood with more carbon dioxide in the air would affect certain plants, he didn’t set

When Lewis Ziska wanted to see how a warmer wood with more carbon dioxide in the air would affect certain plants, he didn’t set

admin2011-03-10  42
问题    When Lewis Ziska wanted to see how a warmer wood with more carbon dioxide in the air would affect certain plants, he didn’t set up his experiment in a greenhouse or boot up a computer model. He headed for Baltimore. Cities are typically 7 degrees warmer than the countryside, as well as big sources of CO2. So Ziska, a plant physiologist at the U.S. Department of Agriculture, compa,ed ragweed growing in vacant lots in Baltimore with ragweed in rural fields—and discovered the dark side of sunny claims that global warming will produce a "greening of planet Earth". Urban ragweed grows three to five times bigger than rural ragweed, starts spewing allergenic pollen weeks earlier each spring and produces 10 times more pollen. In as few as 20 years the whole world will have CO2 levels at least as high as some cities do now. As climate changes due to the greenhouse effect, hayfever sufferers would do well to lay in copious supplies of Kleenex.
   From mosquitoes that carry tropical diseases such as malaria, to plants that produce allergenic pollen, scientists are finding that a warmer, CO2-rich world will be very, very. good for plants, insects and microbes that make us sick. Although the most obvious threat to human health is more frequent and more intense heat weaves, such as the one that killed thousands of people in Europe in 2003, that is only the beginning.
   In the case of plants, it’s not just that they grow faster and shed pollen earlier as the woad warms. The carbon-enriched air also alters their physiology. In a six-year study at a pine forest managed by Duke University, where pipes and fans adjust the CO2 concentration and the air, scientists found that elevated CO2 increases the growth rate of poison ivy. More surprising, by increasing the air’s ration of carbon to nitrogen, elevated CO2 also increases the toxicity of urushiol, the rash-causing oil. "Poison ivy will become not just more abundant in the future," says Ziska. "It will also be more toxic. "
   Plants interpret warmth and abundant CO2as: what a great climate for reproduction. Monitoring stations in Europe are recording higher pollen counts for allergenic grasses and trees, led by birch and hazel, notes a 2005 study by the Center for Health and the Global Environment at Harvard Medical School. Those counts are rising earlier each year: the warming already underway is shifting the pollen season by almost one day per year. By 2017, you’ll be reaching for tissues nine days sooner than you do now.  More good news: in a greenhouse world po]len will be not only more abundant but more allergenic, he and Ziska find.
   Since cities already have the high CO2 levels that the rest of the world can soon expect, "’there is no question these climate-related changes have already begun," says Arlington, Texas, Mayo," Dr. Robert Cluck. "Every summner we’re seeing West Nile virus earlier and earlier, and the higher levels of ozone that come with higher temperatures are increasing the rates of asthma and causing heart and lung damage comparable to living with a cigarette smoker. "
   In a greenhouse world, tropical diseases will expand their range and their prevalence. For instance, alternating floods and droughts—the pattern that comes with climate change—provide perfect conditions for mosquitoes that carry malaria, West Nile and dengue fever. Warming makes mosquitoes bit more. They’ll face fewer predators, too. The frequent droughts expected in a greenhouse world are murder on damselflies and dragonflies.
   As dengue fever, yellow fever and malaria extend their range to higher elevations and higher latitudes, those diseases could appear in the developed woad, too. The southern tier of western and eastern Europe, as well as the southern United States, are most at risk, says Harvard’s Epstein.  Dengue fever has already popped up on the Mexican side of the U.S. border, a worrisome expansion of its current range. Say this for the climate contrarians who insist that a warmer world will he a better, more productive world: if they’re referring to allergens and pathogens, they’re dead right.
The rhetorical device used in the sentence "If they’re referring to allergens and pathogens, they’re dead right" is
选项 A、metaphor.
B、simile.
C、exaggeration.
D、pun.
答案D
解析 推断题。这里作者使用了一语双关。dead有两个意思，一个是作副词，意为absolutely。取此意时，作者的意思是，那些认为变暖的世界将是一个更美好、更多产的世界的人，如果他们指的是过敏原和致病原，他们说的是绝对正确的。前面作者反复提到世界变暖有利于过敏原和致病原繁殖，所以对它们来说，变暖的世界确实是一个更美好、更多产的世界；因为该句前面谈到的是热带疾病在世界的扩散，所以我们可以将作者在此使用dead而不是completely之类的词的用意理解为，强调由温室效应引起的气候变化对人类健康的威胁，这也是全篇文章的主旨。dead的另一个意思是“死的”，作形容词，在这里作补语。因为地球温度升高，有利于过敏原和致病原的繁殖，所以人类健康受到的威胁将更大，死亡率就会更高。当然，这些反气候论者的生命也会受到威胁。在这里我们可以读出作者对这些人的讽刺意味。故答案为[D]。  
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