. —What are you worrying about? —It is ________ there is any chance of being infected by AH1N1 virus.
By the time I _____the railway station, the train _____.
_____ teaching in a university, he also spent some time teaching in a night school.
Why do you want a new job_____ you've got such a good one already?
I couldn’t get to sleep, but _____ all night.
Dr Black comes from either Oxford or Cambridge. I can't remember _____.