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  3. Lead deposits, which accumulated in soil and snow during the 1960’s and 1970’s, were primarily the result of leaded gasoline emi

Lead deposits, which accumulated in soil and snow during the 1960’s and 1970’s, were primarily the result of leaded gasoline emi

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问题    Lead deposits, which accumulated in soil and snow during the 1960’s and 1970’s, were primarily the result of leaded gasoline emissions originating in the United States. In the twenty years that the Clean Air Act has mandated unleaded gas use in the United States, the lead accumulation world-wide has decreased significantly.
   A study published recently in the journal Nature shows that air-borne leaded gas emissions from the United States were the leading contributor to the high concentration of lead in the snow in Greenland. The new study is a result of the continued research led by Dr. Charles Boutron, an expert on the impact of heavy metals on the environment at the National Center for Scientific Research in France. A study by Dr. Boutron published in 1991 showed that lead levels in arctic (北极的) snow were declining.
   In his new study, Dr. Boutron found the ratios of the different forms of lead in the leaded gasoline used in the United States were different from the ratios of European, Asian and Canadian gasolines and thus enabled scientists to differentiate (区分) the lead sources. The dominant lead ratio found in Greenland snow matched that found in gasoline from the United States.
   In a study published in the journal Ambio, scientists found that lead levels in soil in the North-eastern United States had decreased markedly since the introduction of unleaded gasoline.
   Many scientists had believed that the lead would stay in soil and snow for a longer period.
   The authors of the Ambio study examined samples of the upper layers of soil taken from the same sites of 30 forest floors in New England, New York and Pennsylvania in 1980 and in 1990. The forest environment processed and redistributed the lead faster than the scientists had expected.
   Scientists say both studies demonstrate that certain parts of the ecosystem (生态系统)respond rapidly to reductions in atmospheric pollution, but that these findings should not be used as a license to pollute.
What’s the author’s attitude shown in the passage?
选项 A、Supportive to the scientists’ research.
B、Opposed to the lead pollution.
C、Just descriptive of an on-going fact.
D、Positive to the prospect of the solution of lead pollution.
答案C
解析 态度题。此题切忌用常识去解题，而不直接去文章中找答案。尽管文章主题是铅污染，全文中作者体现的态度是描述性的，包括全篇最后一句话，也只是作者引用的科学家的话，故选C项。阅读理解解题来源均出自于原文，而非主观臆断。
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