Combine each pair of sentences using a relative pronoun or a relative adverd

combine each pair of sentences using a relative pronoun or a relative adverd

1. This doctor is famous. You visited him yesterday 
2. My father goes swimming everyday. You met him this morning 
3. The girl is very kind. Her parents work with me 
4. I've sent him two letters. He has received them 
5. The middle-aged man is the director. My father is talking to him 
6. We visited the moument. It was built a hundred years ago