Раскройте скобки, употребляя глаголы в форме Future Perfect
Continuous.
1. He (to do) his lessons for three hours when his friend calls him.
2. She (to read) a book for an hour when I come.
3. You (to work) on your speech when we arrive?
4. They (to discuss) this situation for some minutes when we enter the office.
5. The teacher (to edit) mistakes for two hours when students come to the class.
6. Her brother (to work) at the plant for some years when she finishes her
school.
7. We (to play) guitar for half an hour when you join us.

1. He will have been doing his lessons for three hours when his friend calls him.

2. She will have been reading a book for an hour when I come.

3. Will you have been working your speech when we arrive?

4. They will have been discussing this situation for some minutes when we enter the office.

5. The teacher will have been editing mistakes for two hours when students come to the class.

6. Her brother will have have been working at the plant for some years when she finishes her  school.

7. We will have been playing guitar for half an hour when you join us.

Объяснение:

Используем формулу

Подлежащее + глагол (will + have been + Participle 1).

При этом, Participle 1 - это смысловой глагол с добавлением окончания ing.

Используем данное время, когда хотим сказать, что какое-то действие начнется и будет продолжаться к определенной точке во времени в будущем.

5. На тот момент, когда ученики войдут в класс, учитель уже потратит два часа на исправление ошибок (в тетрадях).