In those days, we had no phones, so we have to keep in touch _________ writing often.
— Have you been here before?— Yes. This is the third time that I ______ to Shanghai.
The number of the teachers who ______ cars in our school ____ increasing very fast.
I hadn't seen her for 10 years, but I ____ her at once.
——What a fine day! Shall we go picnicking?——______. But we need to be home before six o’clock for the football match.
It was freezing last night, so they had the fire___ all night long.