Obama was elected first black president of the United States four years ago and has been elected president again for the next four years.
A. the; the
B. the; X
C. X; the
D. a; a
网友回答
A. the; the
(答案→)B. the; X
C. X; the
D. a; a
解析：
序数词前加the，the first black president第一位黑人总统。而第二空，职位前面省略the.故选B