Puzzled by this strange natural phenomenon, the scientists started to explore every _______ they knew to figure it out.
A variety of books _____________ the children of different ages.
It’s said that this old building has __________ for more than five hundred years.
When there is no time ______ for adding new stories, it’s time to print the newspaper.
As far as I am concerned, education is about learning and the more you learn , ____.
Two hours later, people ___________ from the building on fire.