Since или for. Урок английского языка

1. You haven't smoked sincefor two months.

2. We've been friends with Fred sincefor decades.

3. I haven't slept sincefor 48 hours.

4. We've lived here sincefor seventeen years.

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

6. They haven't visited us sincefor Christmas.

7. Jane has worked here sincefor two weeks already.

8. John and Bob have been working on this project sincefor five months already.

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

10. They've been in love sincefor three weeks.