Select an object on the Source layer <*>: Use a selection set method or press ENTER for all layers.
Select an object of the Type you want <*>: Use a selection set method or press ENTER for all object types.
Collecting all LINE objects on layer LAYER1...
1 object has been placed in the active selection set.
这里的active selection set到底是什么?屏幕上没反应,接下来的命令又不能用这个
active selection set 到底是放哪儿了?请赐教!