Привет помогите пожалуйста английский срочно 20 баллов (В прошедшем времени)

1. Polly has just performed her ballet dance.
2. Ron has not prepared his costume yet.
3. Have the children bought the flowers yet?
4. The children have not invited people to the concert yet.
5. Andy has just finished the posters.
6. Jack has already brought a hat for his tricks.
7. The children have not decided yet what they would do next year.