Since или for. Урок английского языка

1. You haven't smoked sincefor two months.

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

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

4. They have been ill sincefor Monday.

5. Jane has worked here sincefor two weeks already.

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

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

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

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

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