Уроки кончились, но нам нужно было

Уроки кончились, но нам нужно было остаться в школе, мы не могли идти домой.

Результаты (английский) 1:

The lessons were over, but we had to stay in school, we could not go home.

Результаты (английский) 2:

The lessons were over, but we had to stay in school, we couldn't go home.

Результаты (английский) 3:

The class is over, but we have to stay at school. We can't go home.