For
I haven't seen him for ages.
He had been trying to repair the car for fifty minutes by the time the mechanic arrived.
My cousin learns English
for two hours every day.
The woman is practising
the piano for only twenty minutes today.
The girls will have been
making cookies for three hours by the time their guests arrive.
Since
They had been married
since 1970 when her husband died.
The books will have been
there since June by the time she finally notices them.
We have been friends since
the beginning of the school year.
My sister has been attending this school since 2004.
The children have been very quiet since the beginning of the
movie.
