滋病主要破坏人的哪个系统？
参考答案：
免疫系统
Once she has ______nothing can change it, Finally, I had to______.
A．made up his mind ; give up
B．make up her mind ; give out
C．made up her mind ; give in
D．make up his mind ; give off
A．当溜溜球向下自由运动时，动能和重力势能均增加
B．当溜溜球向上自由运动时，重力势能转化为动能
C．溜溜球是通过动能和重力势能的相互转换完成上下运动的
D．溜溜球运动到最底端时，其重力势能最大
