After hospitals buy expensive equipment,they must try to __________ the money they had spent.
The traditional view is ______ we sleep because our brain is “programmed” to make us do so.
______ he referred to in his article was unknown to the general reader.
____ matters most in learning English is enough practice.
Some children want to challenge themselves by learning a language different from ______ their parents speak at home.
______ was most important to her, she told me, was her family.