Men will ________ all the natural resources if they continue consuming them like that.
In the office an electrical engineer is looking through the instructions to know ________ the heat system works before the repair work.
Energy, passion and a burning desire are, you see, ________ true learning takes.
________ is the most important for him is not his job, but his family.
Mary is a humorous and warmhearted woman and that is ________ she is a most popular person in her community.
The organizers promise ________ wins the first prize a chance to go abroad.