已知某几何题的三视图如图所示,其中俯视图中圆的直径为4,该几何体的体积V1,直径为4的球的体积为V2,则V1:V2=( )
A:1:2
B:2:1
C:1:1
D:1:4
— What other rules do you have in your class?— Each student has to a composition once a week.
若x的相反数是3,|y|=5,则x+y的值为____ .