Since или for. Урок английского языка

1. You haven't smoked sincefor two months.

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

3. I haven't slept sincefor 48 hours.

4. We haven't seen Mary sincefor the party.

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

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

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

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

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.