Ответы и объяснения

1. Her new book has been published recently by them
2. Our local museum has been just opened by the town council
3. Their house has been painted by them and now it looks very smart
4. The room has been cleaned by somebody and now it looks nice
5. My dress has been washed by somebdy and now it's clean
6. Dinner has been just cooked by somebody and now it's ready and hot
7. A new theatre in the city has been opened by them
8. The letters has been posted by somebody