说出下列各句中过去分词的句法作用

说出下列各句中过去分词的句法作用
1.There are thousands of (fallen)leaves on the ground.
2.What is the language (spoken) in New Zealand?
3.The door remained (locked.)
4.She was glad to see her children well (taken care of) and everything (arranged) in good order.
5.He was trying to make himself (understood).
6.The professor came in,(followed) by a group of people.
7.(Seen) from the hill,the park looks very beautiful.
8.(Discouraged),I started to leave the place.