91. ______ finding solutions, it is unthinkable to solve all the problems the same way throughout the country.
. Could I have a word with you, mum? — Oh, dear, if you ______.
. All but one _______ take part in the conference ______ tomorrow.
The fire was finally ______ after the building had ______ for two hours.
. Between the two rows of trees ____ the teaching building.
Mary is a lucky girl and she is the only one of the students who______ been to Paris.