Since или for. Урок английского языка

1. I haven't slept sincefor 48 hours.

2. I haven't worked sincefor a mounth.

3. We've been together only sincefor a few days.

4. Jane has worked here sincefor two weeks already.

5. These cherry trees have bloomed every spring sincefor 1980.

6. I haven't talked to him sincefor last week.

7. He's been working in the field sincefor early this morning.

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. Joe and Josephine have been going out together sincefor Valentine's Day.