首先你要有这样的观念：
现在分词的一般式（v-ing) 表示1.主动并进行,但有时表示 2.主动却不进行的动作：
如：1.The man speaking on the stage.=The man who is/was speaking on the stage.
2.The window facing south...=The window which faces south.
过去分词（p.p) 一般表示 1.被动且完成的动作如：The house built last year...=The house which was built last year...
2.完成却不被动的动作如：the fallen leaves= the leaves that has fallen
an escaped convict= a convict that has/had escaped