(2016•黄石)— What did you do last night, Bob?
—First I did my homework, and then I played ______ piano for half ______ hour.
A:the; a
B:/; an
C:the; an
D:a; the
为了更有效预防佝偻病,补钙的同时还应添加( )
为了培养学生勇于承担社会责任,学做负责的公民,某校有计划地开展了一系列教育活动。活动之一是设立“校园文明窗”,供全校学生应聘。具体岗位及要求见下表:
分析材料,完成问题: