1. The house has been pulled down. He lived in the house 10 years ago.
→The house where he lived 10 years ago has been pulled down.
2. The school lies in the east of the town. He once studied in the school.
→The school where he once studied lies in the east of the town.
3. Do you remember the days? On those days we played together.
→Do you remember the days when we played together?
4. We went through a period. During that time communications were very difficult in the rural areas.
→We went through a period when communications were very difficult in the rural areas.
5. After graduation he returned to the small town which he grew up in.
→After graduation he returned to the small town where he grew up.
