II, 93.2 make an -ed clause.
Example: The man was taken to hospital. (he was injured in the accident)
The man injured in the accident was taken to hospital.
=> The man who / that was injured in the accident was taken to hospital.
1, The window has now been repaired. (it was broken in last night's storm)
2 Most of the suggestions were not very practical. (they were made at the meeting)
3, The paintings haven't been found yet. (they were stolen from the museum)
4, Did you hear about the boy? (he was knocked down on his way to school this morning)