【单选题】
{{B}}The Good News{{/B}}
Here’s the good news: our air is cleaner, our lakes are purer, our forests are healthier, endangered species are recovering, toxic emissions are down, and acid rain has diminished dramatically.And yet, if you’ve looked at a newspaper or watched the evening news lately, you might think our environment is under siege(围攻). Media coverage of the environment is heavy on doomsday, but the truth is not at all break: nearly all environmental trends in the United States are positive and have been for years--if net decades.
Eco-legislation, green organizations, corporate cooperation and new inventions have all quietly steered our environment in a positive direction. We can’t afford to be complacent(自满的), though--especially when it comes to greenhouse gases, since global warming is the one huge problem we haven’t really tackleD、But almost every measure taken by government agencies and grass-roots efforts tn improve the environment has shown encouraging results--usually faster than expected and at a lower cost. Now that’s good news.
Scientists and environmentalists think that even the worrisome fact of global warming can be ameliorated(改善). There is a strong scientific consensus that the global warming threat requires action, but if current environmental trends persist and the reduction of most pollutants continues to be accomplished faster and more cheaply than expected, we may be able to control and reduce greenhouse gases in both affordable and practical ways.
Consider some of the environmental improvements the United States has witnessed over the last three decades.
{{B}}ImprovedAir Quality{{/B}}
Take a nice, big cleansing breath.According to theEnvironmental ProtectionAgency, emissions of the primary smog-causing chemicals from cars and trucks have declined 54 percent since 1970, even though the number of registered cars and trucks has more than doubled, from 108,407,000 to 230,428,000, and they are now driven one and a half times as far annually.
Keep breathing, because the fine particulates linked to respiratory disease, including those sometimes seen as soot(煤烟), are down by about one-third since 1979 (though fewer cities were surveyed back then). The level of carbon monoxide, a dangerous odorless gas, is down 53 percent since 1970.And emissions of sulfur dioxide, often the major culprit behind acid rain, are down 49 percent since 1970, despite the fact that the United States now bums far more coal, the main source of this pollutant.
These improvements have translated into better air quality for millions ofAmericans.Between 1976 and 1990, the LosAngeles area averaged some 150 days per year in violation of federal smog standards; in 2004, that figure dropped to just 27 violation days, the fewest ever for that city.
And, in case you are wondering, federal standards have become stricter; not weaker, during this perioD、Of course, there is more to be done-27 smog days in LosAngeles are still 27 too many, andAtlanta, Houston and other cities continue to experience air-pollution problems.But overall, air-quality trends are strongly positive. Now, exhale.
{{B}}Better Water Quality{{/B}}
Other environmental trends are equally encouraging. Water quality has improved, too, and rates of waterborne disease are also in decline. It’s hard to believe, but just a generation ago, factories and municipal plants actually discharged untreated wastewater directly into rivers; today, though some raw sewage often makes it to waterways, almost all wastewater in the United States is treated before discharge.
Even our largest metropolises have seen dramatic changes in their waterways. Remember when the filthy condi
网考网参考答案：B
网考网解析：
细节题。根据题干信息词Scientists and environmentalists定位到第三段首句Scientists and environmentalists think that even the worrisome fact of global warming can be ameliorated (改善)，即：科学家和环境学家认为全球变暖是可以改善的，故选B。 document.getElementById("warp").style.display="none"; document.getElementById("content").style.display="block"; 查看试题解析出处>>
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