Step-by-step explanation:
1)after I read the story's two times,I finally understood the writer's idea
2)before he was a salesman,now he became a teacher
3)Tom came in when she was cleaning the room(not a sure answers)
4)while I was walking down the streets,it began to rain
5)after we won several competitions,he became a captain
6)the telephone rang when I was reading a book
hope this helps