Since или for. Урок английского языка

1. We have received no news sincefor 5:30 pm.

2. You haven't smoked sincefor two months.

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

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

5. They haven't visited us sincefor Christmas.

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

7. John and Bob have been working on this project sincefor five months already.

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

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.