It is required that no smoking ______ in the school.

Without the timely aid from different provinces, the affected people in those areas ________ the difficulty.

—I failed again. I wish I _________ harder.—But you _________.

— How could they keep us waiting for so long? — They got on the bus half an hour ago and they ________ be here in ten minutes, I think.

 “I heard they went skiing in the mountains last winter.” “It _________ true because there was little snow there.”