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 friends with Fred sincefor decades.

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

5. Jane has worked here sincefor two weeks already.

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

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.