Измените каждое предложение, поставив модальные глаголы в сказуемом в прошедшее и будущее время: 1. Не must work hard to finish his experiment. 2. I can devote myself to scientific work. 3. They may carry out these experiments at the laboratory. 4. She can study chemistry at the university.

1. He had to work...
He will have to work
2 I will be able to devote
I could devote
3 they might carry
They will be allowed to carry
4 she could study
She will be able to study