Main clause: I've known her since ...

In sentences with since (referring to time), we normally use present perfect and past perfect tenses in the main clause.

·         I've known her since 1980. (NOT I know her since ... )

·         We haven't seen Jamie since Christmas.

·         I was sorry when Jacky moved to America; we had been good friends since university days.

However, present and past tenses are also occasionally found, especially in sentences about changes.

·         You're looking much better since your operation.

·         She doesn't come round to see us so much since her marriage.

·         Since last Sunday I can't stop thinking about you.

·         Things weren't going so well since Father's illness.

Some common rules for advance learners.