1/ we worked very hard for the exam. Then we passed it.
-> before we passed the exam, we had worked very hard
2/ first my sister considered what to say. Then she decided to talk to her headmaster.
-> after  my sister had considered what to say, she decided to talk to her headmaster
3/ we(lived) ... In new york for ten years and then we (move)... Here in 1987.
-> have lived/ moved
4. I/go swimming /yesterday. 
-> I went swimming yesterday
5. After they had gone, i ... (sit) down and... (rest).
-> sat/ rested