John fell asleep ______ he was listening to the music.A.after B.before C.while
They ______ going to school on foot before they went to high school.
--- Do you know Tom very well?--- Yes, he and I _______ friends since we met in yangshan the year before.
Italy is famous for _____.
I won’t go to the concert because I ________ my ticket.
_______ great fun it is to fly in a balloon!