Since или for. Урок английского языка

1. We've lived here sincefor seventeen years.

2. I haven't worked sincefor a mounth.

3. My boss has been away sincefor half a day only.

4. They haven't visited us sincefor Christmas.

5. You have been watching TV sincefor hours.

6. He hasn't played the piano sincefor he was a boy.

7. They have been raising horses and cows on their farm sincefor many years.

8. He worked at that company sincefor ten years before he retired.

9. New ideas have been put into practice sincefor he was elected our leader.

10. They've been teaching here sincefor quite a long time.