base, foundation, ground 辨析

base, foundation, ground这一组名词都有"基础"的意思。
base n.指具体的有形的基础，也可指物体的底部、基部；基地，总部。
They use their apartment in New York as a home base from which they travel frequently.他们把纽约的公寓作为他们频繁出行的大本营。
foundation n.本义指建筑物的地基，含有坚实的基础的意思；基金会。
The foundation for our house is made of cement.我们房子的地基是水泥打下的。
ground n.地面，土地，也指地域，水底，海底。