They have announced that they will invite only three of us to the party.

问题描述:

They have announced that they will invite only three of us to the party.
要求主句转为被动语态:
That they will invite only three of us to the party has been announced.
It has been announced that they will invite only three of us to the party.
第一句如果错了,错在哪了?

都对.第一和第二句是等效的,第二句只是用了形式主语it来替代了逻辑主语that从句而已.