(1)The man is a miner.  He lives opposite our house.

The man who/that lives opposite our house is a miner.  

(2)He will visit the famous dam next month.  It was built in 1900.

He will visit the famous dam next month which/that was built in 1900.  

(3)I want to talk to the boys.  Their homework hasn’t been handed in.

I want to talk to the boys whose homework hasn’t been handed in.