锰锌干电池在放电时总反应方程式可以表示为:Zn(s)+2MnO2+2NH4+=Zn2++Mn2O3(s)+2NH3+H2O,在此电池放电时正极(碳棒)上发生反应的物质是( )
A:MnO2和NH4+
B:Zn
C:碳
D:Zn和NH3
下图是李奶奶养的鸡、鸭、鹅情况统计表。请你算一算鹅在扇形统计表中的圆心角是____ °
—I was born _______ May 10th.
Let's work together ____ (make) China Dream come true.
He enjoys _____computer games.