had been 和 Having been 区别?____ by an American university , I finally flew to XX on August 1, 1988Having been invited / Had been invited为什么选后面一个?

had been 和 Having been 区别?____ by an American university , I finally flew to XX on August 1, 1988Having been invited / Had been invited为什么选后面一个?
had been 和 Having been 区别?
____ by an American university , I finally flew to XX on August 1, 1988
Having been invited / Had been invited
为什么选后面一个?

had been 和 Having been 区别?____ by an American university , I finally flew to XX on August 1, 1988Having been invited / Had been invited为什么选后面一个?
had been是过去完成时,having been是现在完成进行时.
《过去完成时》是过去某个时间做的事,并且已经做好.
《现在完成进行时》是可能是过去开始的,但是持续到现在才完成或者还在进行.
这句中有具体的时间,是过去已经完成的事,所以选过去完成时.