EX6:
8. Articles which customers have bought during the sale can't be exchange 
9. This man mustn't moved, hê is too ill
10. When this street has been widened, residents will be kept awake by the road of the traffic all night
11. This skyscrapers will have to pulled down as the town planinig regualtions hasn't complied with
12. The accident ought to have been reported to the police
13. It must be dry-cleaned
14. After that they must be returned
15. He will have to be lef here 
EX7.
1. B
2. D

7. Those books should have been taken to the library.
8. Articles (which have been) bought during the sale cannot be exchanged.
9. This man mustn’t be moved; he is too ill/ he is too ill to be moved. He will have to be left here.
10. When this street has been widened the residents will be awaked by the roar of the traffic.
11. This skyscraper will have to be pulled down as the town planning regulations have not been complied with.
12. The accident ought to have been reported to the police.