单项选择题
A.250 tons B.450 tons C.650 tons D.950 tons
A.The twenties. B.The thirties. C.The forties. D.The fifties.
A.To show how American society has changed. B.To compare two different ways of American life. C.To tell the meaning of the American people's attitude towards life style. D.To prove that modern life is better than the life in the past.