I want to know your age.
A:How are you?
B:How old are you?
C:What's your name?
D:When is your birthday?
在中国历史上,分裂和统一的局面曾交替出现。结束东汉末年以来近百年分裂局面,实现全国统一的关键人物是( )
在半径为r的球内有一内接正三棱锥,它的底面三个顶点恰好都在同一个大圆上,一个动点从三棱锥的一个顶点出发沿球面运动,经过其余三点后返回,则经过的最短路程是( )