Поставьте последующие предложения в прошедшее и будущее время, используя подходящий эквивалент

1) They can study many languages at our academy. - They could study many languages at our academy. - They will be able to study many languages at our academy.

2) He may watch this project. -  He was allowed to watch this project. -  He will be allowed to watch this project.

3) These problems must be solved. - These problems had to be solved. - These problems will have to be solved.