这是CNN新闻上的关于北京大兴机场的文章，其中有这么一段：
All of this coinciding with the seventieth anniversary of the founding of communist China.
In fact, to inaugurate this new airport, President Xi Jinping himself was here.
He had a crowd that was gathered, of dignitaries, a lot of airport officials as they begun this new chapter
in air travel right here in Beijing.
为什么是was gathered被动呢？不理解。