---What’s that unpleasant noise?---Oh, the road before the main gate ______.

--- Oh, dear. I forgot the air tickets.　--- You ______ something.

I wonder why Jenny ________ us recently. We should have heard from her by now. 

As soon as the children _____ themselves in their seats in the classroom, the bell rang.

The fire, believed to     due to illegal construction on the building’s roof, was brought under control after an hour.