Is it only on the world market ________we can prove the competitiveness and quality of our goods?
They were all very tired, but ________ of them would stop to take a rest.
Come and see me whenever ________.
--The plane is due to take off at 7∶50 from the airport. --________ we fail to arrive there in time?
--They ________ out the problem, but failed. --What a shame ! I never thought it was going to happen like that.
--Let’s go there by taxi. --It’s not far from here, I prefer ________.