关于机械运动和参考系，以下说法不符合实际的是（　　）

A．一个物体相对于别的物体的位置变化，叫做机械运动

B．参考系必须是和地面连在一起的物体

C．参考系就是不动的物体

D．任何物体都可以被选作参考系

— I think it was his excitement for his success in the first half that led to his eventual failure in the game.

— You bet. Old sayings never fail, “________”

A．Failure is the mother of success

B．Pride goes before a fall

C．A hero is nothing but a product of his time

D．A fall into the pit, a gain in the wit