1. They have lived there since 1990.
They have lived there for 9 years.
2.He haven't had a letter from her since March.
He haven't had a letter from her for 3 months.
3. I have been here since half past one.
I have been here for 3/4 hours (nu se vede bine cat e ceasul in imagine).
4. She haven't played tennis since July 1st.
She haven't played tennis for fourteen days.