1. When I (to enter) the classroom, the teacher (to give) a lecture for fifteen minutes.
2. My brother (to work) as a shop-assistant for six years before he (to decide) to get a higher education.
3. Father (to come) home late last night. His little son (to sleep) for three hours.
4. My parents (to return) to Russia last month. Before that they (to work) in the USA for five Years.
5. The workers (to discuss) the problem for forty minutes, when the chief engineer (to appear).
6. Before Nick (to go) to see a dentist, he (to suffer) from a toothache for a week.
7. The rain (to stop) on Thursday. It (to rain) since last week.