= water which is polluted
= the seats which were reserved
= the animal which was trapped
不及物动词的过去分词不表被动，只表示动作发生在谓语动词之前，含有动作完成，动作结束之含义。
= the leaves which have fallen
= the sun which has risen
过去分词作定语也可用作非限制性定语，前后用逗号隔开。
The books, written by Guo Jingming, are very popular with teenagers. 这些书是郭敬明写的，深受青少年的喜爱。
Some of them, born and brought up in rural villages, had never been to Beijing. 他们中的一些人，在农村出生并长大，从没过北京.
The book _written by the farmer (一本农民写的书) is very popular.
The building built last year (去年建的楼房) now collapsed in the Wenchuan earthquake.
The problem discussed at the meeting yesterday (在昨天会议上讨论的) was very difficult to solve.
The window broken by that naughty boy被那个顽皮男孩打破的) is being repaired.
