Since или for. Урок английского языка

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

2. We've lived here sincefor seventeen years.

3. I haven't worked sincefor a mounth.

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

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

6. Dinosaurs have been extinct sincefor over 60 million years.

7. Jane has worked here sincefor two weeks already.

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

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

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