A:14
B:4
C:21
已知平面α截一球面得圆M,过圆心M且与α成π3角的平面β截该球面得圆N若圆M、圆N面积分别为4π、13π,则球面面积为( )
—I'm sorry I stepped outside for a smoke.I was very tired.
—There's no________for this while you are on duty.
未成熟的葡萄吃起来是酸的,这种酸性的物质主要存在于