Поставьте глаголы в past indefinite, present perfect или past continuous.
1. When the coach (to return ) the students (to do) the forth exercise.
2. The students (to do) all the exercises before the coach (to return).
3. We (to discuss) two important questions at the last meeting/
4. The runner already (to set) a new record before his friend came to the contest.
5. We (to discuss) all the problems by 5 o`clock in the evening.
6. When you phoned, the students (to do) morning exercise

1.     Returned, were doing 2.     Have done, returned 3.     Discussed 4.     Has already set 5.     Had discussed – past perfect  - by - употребляется, когда действие завершилось до какого-то времени в прошлом: Мы обсудили все проблемы к 5 часам вечера.6.     Were doing