Write f beside the expressions we use with for and s beside the expressions we use with since​

1. f

2. s

3. f

4. s

5. s

6. f

7. f

8. s

9. s

10. s

11. f

12. s

13. f

Write fbeside the expressions we use with for and s beside the expressions we use with since.

for a week

since 10:30

for half an hour

since I last saw her

since then

for a long time

for a while

since 1996

since this morning

since I left school

for three years

since we met

for ages