关于英语

首先我想说的是..没有 be having been doing/gone这样的用法

having done和have done的意义都一样..只是当在句子中的成份不同时才表现不同...having been doing也是

如:
I [have known] everything before [having been doing] these.
我在干这些事情(现在还在干)之前已经了解了所有的东西了.

介词before后面的having been doing其实可以用I have been doing代替.

还有如:
Having got the ticket, I will/would set out tomorrow.
得到车票(飞机票)了,我明天就会出发.

开头的having是分词作状语,前面整部分形成状语从句,表示一种条件

如:
Having been writing for so long, I feel/felt really tired.
写了那么久的文章(还在写), 我感到很累了.
可以表示过去的..因为having been writing for so long只是表示一种原因, 是状语从句, 不是指现在进行时.上面那句话也是.