When a fire ______ at the National Exhibition in London, at least ten priceless paintings were completely destroyed.
_____everybody is here, Let’s begin our meeting.
He must have passed this way, _____here are his footprints.
“Why can’t you do it now?” “_____I’m too busy.”
_____it is raining, we had better take a taxi.
It was_____he was ill that he was absent yesterday.