过去分词作状语的时态问题

过去分词作状语的时态问题
过去分词作状语可以表示完成,是否代表分词动作发生在谓语动作之前?
Written in a hurry,this article was not so good!
Seen from the hill,the city looks very beautiful.
但是又有知识点说分词动作发生在谓语动作之前用having done 、having been done 结构?
如 Having been shown around the Water Cube ,we were then taken to see the Bird's Nest .
究竟怎么区分呢?