英语中分词being done 与 having(been) done区别是什么?

eing done 是被动的进行时,意思是正在被做
例,The car is being mended.
having been done表示该动作先于主句谓语动词.
losr 只是瞬间动作,没有being lost
现在分词的被动语态：一般式（being done)表示与谓语动词同时发生的被动的动作,完成式（having been done)
The promblem being discussed is very important.