Where have all the young girls gone? Where did they all gone? 什么意思

1.Where have all the young girl gone ?

have gone to 结构，表示去某地了，现在还没有回来。如：Where is Tom? He has gone to the library .

2.Where did they go ?仅表示过去的动作，与现在没有联系。而且这种时态常带有过去的时间。