IV:
1. They usually eat ___theirs ___ lunch at the Rita Cafeteria.
2. The man is studying ___his___ English now.
3: We write letters to ___our___ friends once or twice a month.
4: John's new jacket and ___mine___ are very similar.
5: Her father and mine have offices in the same building ___ours___ is on the first floor, but ___theirs___ is on fourth.