The author thinks of the Federal effort in dealing with stationary pollution sources as__________.
A.efficient B.excellent C.unsustainable D.unsatisfactory正确答案D
The author thinks of the Federal effort in dealing with stationary pollution sources as__________. 
The author thinks of the Federal effort in dealing with stationary pollution sources as__________.
A.efficient B.excellent C.unsustainable D.unsatisfactory正确答案D
