We use since with the starting point. Examples: since January, since Monday, since last year.
We use for with a period of time. Examples: for two hours, for weeks, for ages.
In negative sentences, we can use in and for with the same meaning.
Fill in the blanks with for, since or in.
Answers
1. I haven’t seen him in / for months.
2. He has been absent for several days.
3. They have lived all their life here.
4. This has been going on for several months.
5. He has been unwell since he moved to the city.
6. Have you been waiting for long?
7. It hasn’t rained in/for months.
8. I have known him for a long time.
9. We have known each other since our childhood.
10. I haven’t been to the theatre in / for ages.
11. She has been acting since she was three.
12. I have been teaching English for twenty years.
