Our country is the center of the nature geography distributing of the clove, and is the origincenter place for planting the clove.
我国是丁香属的自然分布中心，同时也是丁香栽培的起源中心。
2
I've used eight vertices (the cube's corner points) and placed the cube's center at the coordinate system's origin.
我在这里使用了8个顶点(立方体的顶点)并使立方体的中心与坐标系的原点相重合。
3
So, switching the area, moving the area to the other side, I'll get double integral of xdA is the area of origin times the x coordinate of the center of mass.