单项选择题
The current situation of African-Americans presents（）
A.a favorable picture B.a negative picture C.a mixed picture D.an encouraging picture
单项选择题 Between 1960 and 1990,a large number of people moved from（）
单项选择题 In the last great population movement,a large number of people moved to（）
单项选择题 According to historians and specialists in demography,there are（）great population movement(s)in the history of the United States.
