How can you expect him to make any progress _____ you never give him a chance to have a try?
_______ on time, this medicine will be quite effective.
When I handed the report to John, he said that George was the person _______.
He is a man of few words, and seldom speaks until _______ to.
Though I have often heard this song _______. I have never heard you _______ it.
Tony was very unhappy for _______ to the party.