请选择ABC9?7N8|4{We ___ at the airport all morning before there was any news about our flight.4u:j.t)H3O'D8K*X8A/q.i2y1O
A. have been waiting4u:j.t)H3O'D8K*X8A/q.i2y1O
B. had been waiting4u:j.t)H3O'D8K*X8A/q.i2y1O
C. are waiting4u:j.t)H3O'D8K*X8A/q.i2y1O