过去分词与现在分词被动式的区别

过去分词在被动的同时,还表示完成,而现在分词被动式在被动的同时,还表进行.
Built in 1501,the bridge is over 500 years old.这座桥建于1501年,已有五百多年的历史.
Who is the woman being operated on?正在动手术的女人是谁?
但有时它们也可表示相同的意思.如：
Written in haste,the book has many mistakes.这书因写得仓促,所以错误不少.
Being written in haste,the book has many mistakes.这书因写得仓促,所以错误不少.
Having been written in haste,the book has many mistakes.这书因写得仓促,所以错误不少.
有时虽然所表示的时间概念相同,但有细微区别：
Having been show the lab,we left.被领着看了实验室后,我们就离开了.
Shown the lab,we left.被领着一看完实验室,我们就离开了.(有一种急促感)