The room, although_________ to be kept locked, was often left open.

We will have a meeting next week, but we don’t know ＿＿＿＿＿. 

Nelson Mandela is，__________ the greatest man of the 20th century，certainly among the most extraordinary leaders．

——Did you know any French before you arrived in Washington?——Never ____ it, actually.

It was announced that only when the fire was under control _______ permitted to return to their homes.