1.The school year starts in the first of September.
→The first of September is the day when the school year starts.
2.My brother stopped smoking becouse it is bad his health.
→The reason why my brother stopped smoking is it is bad for his health.
3.We went to Shanghai on our school trip.
→The city where we went on our school trip is Shanghai.
4.I most like the late show on TV.
→The TV programme which I most like is the late show.
5.My father works in a factory that makes telephones.
→The factory where my father works makes telephones.
6.She did her homework in this room.
→This is the room where she did her homework.