Since или for. Урок английского языка

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

2. I haven't worked sincefor a mounth.

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

4. Jane hasn't been back to Hungary sincefor last year.

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

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

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

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

9. They've been teaching here sincefor quite a long time.

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