【单选题】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 Cl...
A.
lead deposits in arctic snow are on the increase
B.
the Clean Air Act has not produced the desired results
C.
the US is the major source of lead pollution in arctic snow
D.
lead will stay in soil and snow longer than expected
【单选题】根据下面材料,回答题。 Lead Pollution (铅污染) Lead deposits, which accumulated in soil and snow during the 1960&39;s and 70&39;s, were primarily the result of leaded gasoline emissions originating in the United St...
A.
the US is the major source of lead pollution in arctic snow
B.
the Clean Air Act has not produced the desired results
C.
lead will stay in soil and snow longer than expected