【简答题】Passage Three Questions 31 to 35 are based on the following passage. Intel chairman Andy Grove has decided to cut the Gordian knot of controversy surrounding stem cell research by simply writing a che...
【单选题】Passage Three Questions 21 to 25 are based on the following passage. Lead deposits, which accumulated in soil and snow during the 1960's and 70's, were primarily the result of leaded gasoline emission...
A.
the Clean Air Act has not produced the desired results
B.
lead deposits in arctic snow are on the increase
C.
lead will stay in soil and snow longer than expected
D.
the US is the major source of lead pollution in arctic snow