分词done和having been sone有何区别?

现在分词完成式having been done和过去分词done的用法区别having been done和done的意义有时非常接近,那就是它们都可以表示发生在谓语动词前的被动动作,甚至有时可以互换。例如：Having been weakened by successive storms,the bridge was no longer safe。= Weakened by successive storms,the bridge was no longer safe。但下列情况只用done：过去分词done只表示被动,不表示特定的一次,也没有一定的时间性,例如：Seen from on the top of the hill,the park looks more beautiful。2。过去分词done只表示状态,不表示动作,例如：The road was covered with fallen leaves。United,we stand; divided,we fall。3。过去分词done只表示完成,不表示被动,这类动词一般由不及物动词产生,例如：With all his friends and money gone,he felt helpless。这样的动词还有,fallen,boiled,baked,developed等。4。现在分词having been done一般不能作后置定语,用过去分词替换,但作非限制性的后置定语是可以的。例如：The question having been discussed for thousands of years has now been solved。(×)The question discussed for thousands of years has now been solved。( √)The question,having been discussed for thousands of years,has now been solved。( √)