Since или for. Урок английского языка

1. We have received no news sincefor 5:30 pm.

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

3. I haven't slept sincefor 48 hours.

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

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

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

7. She has been in hospital sincefor Monday.

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.