13.With the car________down halfway on the road, we had great difficulty walking home in the snow.
________ many changes have _______, we should keep pace with the changes too.
He said it was this classroom _______ he found his lost watch and _____ he would take good care of it from then on.
_________ wants to enter for the match should reach the given standard.
I hate ______ when people call me by my nickname (绰号).