Since или for. Урок английского языка

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

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

3. They haven't visited us sincefor Christmas.

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

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

6. They have been raising horses and cows on their farm sincefor many years.

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

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.