My calculations were based on the ________ that house prices would remain steady.

To save some of the human languages before they are forgotten, the students in our school started a discussion “Save Our ________”

Some countries are increasing their use of natural gas, and other forms of __________. 

Please don’t speak at one time. George may take the ________ after the two women each say a few words.

Whether by accident or _________ , he arrived too late to help us.