你的理解是正确的
在被动语态里常出现两个或两个以上助动词
be being done
have been being done
have been done
will have done
will be doing
will have done
will have been done
should have done
would have done
might have done
could have done
my be doing
could be doing
must have done
must be doing
这些都是两个或两个以上助动词 然后一起合成谓语
He is being interviewed now.
如果去掉being,he is interviewing now就变成了主动语态了 从被面试变成面试别人了