They were walking along the shore _______ a huge wave appeared out of nowhere, sweeping them out to sea

It is hard for him to stop __________ though he has had a lot of diseases.

_____in the queue for half an hour, Tom suddenly realized that he had left his wallet at home.

So far this year we ______ a fall in house prices by between 5 and 10 percent

He must stay at home to look after his ____ mother .She has been _____for a week.