________history of the American South is________history of suffering, also one of hope and success.[ ]

A. A; the      

B. The; the

C. A; a  

D. The; a

精神发育迟滞起病于（）

A.婴幼儿期

B.学龄期以前

C.15岁以前

D.18岁以前

E.25岁以前