Since или for. Урок английского языка

1. Jane hasn't been to America sincefor 1981.

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

3. I haven't slept sincefor 48 hours.

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

5. I've read two books sincefor the weekend.

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

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

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

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

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