Since или for. Урок английского языка

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

2. I haven't met Jill sincefor the end of the school.

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

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

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

6. I haven't talked to him sincefor last week.

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

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