Ответ:
1. Students wrote for two hours when the teacher told them to stop.
2. I wait more than two hours. Where have you been ?
3. Tomorrow there will probably be snow
4. He closes all windows before leaving the house.
5. She did the cleaning yesterday at 6 o’clock.
6. He was cleaning the car when the phone rang, so he did not answer.
7. “How long have you been working for this company?” “It's been ten years now and I like it here.”