According to the traffic rules, you _________ wear the safe belt while you are driving.
With housing prices rising sky – high, I doubt whether I can afford a house___________in my life time.
--- What about___________concert? --- It was too boring, you know, _____________concert for me.
It’s already 10 o’clock. I wonder how it that she was two hours late on such a short trip.
_______ what would happen, none of them could find a way out.
Students who pass the test will be ______to the next grade, as has been announced.