In sentences with since, we normally use present perfect and past perfect tenses in the main clause.
- I met him ten years ago and have admired him ever since.
- We haven’t met since her marriage.
- They have known each other since 1975.
- We had been friends since university days.
Present and past tenses are also occasionally used. This often happens in the structure It is/was … since …
- It is just a week since we arrived here.
- It was ages since our last game of tennis. (OR It had been ages since our last game of tennis.)
Tenses in since-clauses
Since can introduce its own clause. The tense in the since-clause can be perfect or past, depending on the meaning.
- I have known her since we were at school together.
- I have known her since I have lived in this street.