When I was passing the Town Hall, I heard the clock ______ twelve.
Bad habits, ____formed, are difficult, and sometimes impossible to shake off.
Only when you leave your parents for college education _______ how much you love them.
The cause he had devoted himself to _______ a perfect success.
Many experts believe that teachers’ development is _____ the key to better education lies.
Evidence has been piled up_____drinking water after getting up in the morning contributes to one’s health.